Issues I’ve encountered building an app with magic links:
1. Include a fallback sign-in code in your magic link, in case the user needs to log in on a device where accessing their email isn’t practical.
2. Make sure the sign-in link can handle email clients that open links automatically to generate preview screenshots.
3. Ensure the sign-in link works with email clients that use an in-app browser instead of the user’s preferred browser. For example, an iOS user might prefer Firefox mobile, but their email client may force the link to open in an in-app browser based on Safari.
We went to a lot of trouble to make our magic link implementation work with anti-phishing software, corp link checkers and more. https://github.com/FusionAuth/fusionauth-issues/issues/629 documents some of the struggle.
I think that a link to a page where you enter a one time code gets around a lot of these issues.
I arrived at the same conclusion after going through the steps and seeing that some corporate systems mark the login link as malicious, and there’s nothing I can do about it.
Sending a code goes around a lot of issues.
Also: Safari can autofill codes from both email and text messages on macOS and iOS. It then automatically deletes the message too.
https://www.webnots.com/how-to-autofill-verification-codes-i...
Why not just support a password?
Only having magic links gets you a load of stuff for free,
Higher level of security than just user+pass (w/ forgot password)
Email verification
Lifecycle management - in a SAAS when a user no longer has a corporate email, they can defacto not log in, wheras with a user+pass you need to remember to remove their account manually on each SAAS or have integration with your AD (for example)
It’s not a higher level of security than password-based authentication. Why do you state that?
One-time email verification is not the same as security model as magic links. Magic links require instant access. Many security sensitive sites require a time delay and secondary notification for password reset links, which you can’t reasonably do for login links.
Lifecycle management is an interesting point. There are some underlying assumptions that might not hold though—losing an email doesn’t necessarily mean downstream accounts should be auto disabled too. Think Facebook and college emails, for example.
> It’s not a higher level of security than password-based authentication. Why do you state that?
Personally I'm no fan of magic links.
But the people who do like magic links would say the typical 'forgot password' flow is to send a password reset magic link by e-mail. That means you've got all the security weaknesses of a magic link, and the added weaknesses of password reuse and weak passwords.
Of course you can certainly design a system where this isn't the case. Banks that send your password reset code by physical mail. Shopping websites where resetting your password deletes your stored credit card details. Things like that.
It's not about 'liking' magic links;
That means you've got all the security weaknesses of a magic link, and the added weaknesses of password reuse and weak passwords.
Is objectively true. I don't really 'like' magic links but I think they're a very easy to implement and simple to use for infrequently accessed systems. Arguably easier than user/pass and certainly more secure.
Even with those assumptions (which I question), it is only a higher level of security if you assume that your users are reusing passwords, or using low entropy passwords. Neither would apply if they are using a password manager, which a growing majority of web users are.
> It’s not a higher level of security than password-based authentication. Why do you state that?
It could be, depending on how the user has secured their email inbox access. I know I pay a lot more attention to my inbox than some random account. I don't have data, but I think this is true of most people.
I'm also more likely to enable MFA on my email account than I will on every random account I sign up for. And as far as the account providers, I trust the big email providers to be more secure than some random website with an unknown level of security.
You raise some valid points about tying access to a third party and what makes sense. It's not a simple issue.
That's a fair point, but does time delay or secondary notification (the latter could be done for magic links of course) really outweigh the practical security risk of password reuse, attacks, leaks etc? I would argue not, unless the user had a insecure email account for some reason.
Re Lifecycle management; Unless you're also linking a phone number or some other "factor" I think in a traditional user+pass scenario you're also SOL if you lose access to your $Email1 before you update your account to use $Email2, as changing your email to $Email2 would usually send a email to $Email1 to confirm the action. In that case you're in the same position as magic link login + email change functionality. Similarly Lifecycle management only comes for free if you don't implement email change functionality.
It's incredibly annoying to the user though
Oh, we support passwords! (And passkeys, and social login, and OIDC, and SAML.)
Just want to make sure magic links work as well as they can.
Different folks have different requirements, and since we're a devtool, we try to meet folks where they are at.
We actually recently added a feature which lets you examine the results of a login, including how the user authenticated, and deny access if they didn't use an approved method.
One weird reason I've personal run into: when building on the edge, like with cloudflare workers, you can run into timeout issues because of how long password hashing takes.
That should be only if you're on the free plan that has a 10ms time limit. Paid plan gets 30 whole seconds which is plenty of time to hash lots of passwords.
Because ≈everyone reuses passwords and so accounts get taken over.
A majority of internet users (>60% in 2024 and growing) use password managers and don’t reuse passwords.
In my experience 60% seems too high even for supposedly technical users (ref: I work in a dev firm), at least away from their jobs.
I definitely don't believe it for the wiser population (my gut, again based on people I know, says the number is more like 10%, maybe 15). Even the 36% figure on the report on security.org posted above seems dubious, I suspect they have some bias in their survey. Unless that is some people who use the iCloud password manager for some things and no password manager for everything else, so it isn't claiming 36% routinely use a password manager away from a few key accounts.
Do you have a source for that number? 60% seems extremely high based on non-technies I know.
Agreed. I'd be thrilled if it were true, though! Because password reuse (esp without MFA) is a big problem.
This is an extraordinary claim on two counts:
1. Sixty percent seems astronomically high, do you have a source?
and
2. Most "normal" non-tech-savvy people I know who do use a password manager (which I've typically installed for them), are revealed a while later to still use a variation of password reuse : either storing the same password per category of websites, or having a password template they use on all sites, e.g. "IdenticalSecretWord_SiteName"
I don't have the source, but don't think 1Password/LastPass/KeePass. Think the "would you like to save this login" built in to Chrome, Firefox, Edge, Windows, and iOS. These days, you have to opt-out of password management.
Right, use of a Password Manager does not imply they are using Password generation - it may just mean they click "Save this password" after logging in using a re-used password.
I'm surprised. >60% seems high even for tech literate software engineers!
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So what?
1) It means your users will complain that their account was hacked (even if it was their fault) and might cancel their service
2) hackers can exploit your system which hurts you (you are a VPS provider and someone mines crypto and you have to wave it for PR) or you run an email service and someone uses your app to spam (which hurts your email rep) etc.
one times codes are very vulnerable to phishing. users are prone to entering codes on any resembling website
I was gonna argue that you can fix this but I realized that you’re right. It’s a MITM attack where there’s really no way to stop it, same as passwords. It’s basically the same feature (sign in in a different browser) that also lets attackers in.
That said, here’s how I would mitigate it:
- Like usual, time based limits on the code - Code is valid only for the initiating session, requiring the attacker to create a paper trail to phish
If you do have a magic link & want to use code as backup for authenticating a different device/browser, you could:
- Compare IP and/or session cookie between the initiating and confirming window. On match, offer login button. On mismatch, show the code and a warning stating how it’s different, eg ”You are signing in a different device or browser, initiated from $os $browser in $city, $country, $ip - $t minutes ago.”
It’s not perfect though and may still be prone to phishing.
I've had success with sending a code, and the link takes you to a page where the input is pre-filled with the code, and you just have to click "Login".
Yup, that's a good option. Any kind of user action like a form submission is less likely to run afoul of a link checker.
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> I think that a link to a page where you enter a one time code gets around a lot of these issues.
I've done both in my SaaS product - link is GET with the OTP in the link, the target page checks if the link is in the URL, and if not, then the user can type it in.
Only for signup, though. For sign-in, the default is to always have the user type it in.
These days there's also to consider that some Mail Threat Protection Tools (at least Microsoft Defender in Exchange Online does this) click links in Mails to check them.
Recently ran into this issue as new mail accounts got confirmed automatically and magic links were invalid when the user clicked them, because Microsoft already logged in with it during checking.
Come to think of it, magic links by definition violate the principle that GET requests should not change state. Defender & preview tools are actually following the established norms here - norms that were established decades ago precisely because we hit the more broad problem with C, U & D parts of CRUD, and collectively agreed that doing destructive operations on GET requests is stupid.
You can GET a <form> which POSTs when you click the "log in" button.
Yes, but the GET itself isn't changing any state. The state changes only after clicking on the button. This is OP's point.
TeMPOraL said, "magic links by definition violate the principle that GET requests should not change state". That is a reasonable thing to think, but it is not true, because you can GET a <form> which POSTs when you click the "log in" button, unless you think a link to such a <form> page should be excluded from the definition of "magic link".
> unless you think a link to such a <form> page should be excluded from the definition of "magic link".
Yes. Linking to a form requiring user to press a button to submit an actual POST request is one proper way of doing it, and won't confuse prefetchers, previewers and security scanners - but it lacks the specific "magic" in question, which is that clicking on a link alone is enough to log you in.
Can't really have both - the "magic" is really just violating the "GET doesn't mutate" rule, rebranding the mistake we already corrected 20+ years ago.
(EDIT: Also the whole framing of "magic links" vs. passkeys reads to me like telling people that committing sins is the wrong way of getting to hell, because you can just ask the devil directly instead.)
Aha, then we agree on the facts, just disagree about nomenclature.
Your theological analogy is hilarious!
In your example, it seems to me that the POST request is the action that changes the state.
Agreed.
This is the way.
That seems like a really thoughtless idea.
What can you do to prevent automatic confirmation in that case?
I run an authorization service that allows to log-in using magic links and we managed to solve this. First approach was for the link opening GET request to do not log the user in, but to include an HTML page with JavaScript that issued a POST request with a code from the link to log the user in. This worked well for a long time, because email scanners were fetching links from emails with GET requests but did not execute JavaScript on the fetched pages. Unfortunately, some time ago Microsoft tools indeed started to render the fetched pages and execute JavaScript on them which broke the links. What works now is to check if the link is open in the same browser that requested the link (you can use a cookie to do it) and only automatically login the user in these cases. If a link is open in a different browser, show an additional button ('Login as <email address>') that the user needs to click to finish the login action. MS tools render the login page but do not click buttons on it.
The issue that MS tools introduced is broader, because it affects also email confirmation flows during signups. This is less visible, because usually the scanners will confirm emails that the user would like to confirm anyway. But without additional protection steps, the users can be signed up for services that they didn't request and MS tools will automatically confirm such signups.
> check if the link is open in the same browser that requested the link (you can use a cookie to do it) and only automatically login the user in these cases. If a link is open in a different browser, show an additional button ('Login as <email address>') that the user needs to click to finish the login action.
Thanks for checking if it's the same browser. Some companies don't care about that (cough booking cough) so harmful actors just spam users with login attempts in hope a user will click by accident. And puff, random guy gets full access to your account. I got those every day, if I ever needed to login this way I would not be able to figure out which request is mine.
Wouldn't that just log you in on the browser doing the clicking, instead of the attackers browser?
You mean in the booking example? They logged in the browser that... requested access. So basically anyone that knew your login/email.
I think it should check if browser requesting is the same as the one confirming, or just drop that whole dumb mechanism entirely.
Ok, what if an email has "click this link if it was you who tried to log-in", or "if it wasn't you"?
Will Microsoft automatically authenticate malicious actors, or block yourself from services built with assumptions that the email client won't auto-click everything?
Login links from my service were automatically clicked and rendered and I know that other services discovered similar problems. Based on this I think that it is very likely the case with all the links in emails, but I don't know if there is any additional heuristic involved that would treat some links differently.
See also this issue which suggests that all links are opened: https://techcommunity.microsoft.com/discussions/microsoftdef...
Note that this doesn't affect all Outlook users, this Microsoft Defender for Office 365 is a separate product that only some companies use.
That check for the same browser is a great idea. Thanks!
This can be annoying when you intentionally want to log in to a browser that is not the one making the request, such as an in-app browser.
> But without additional protection steps, the users can be signed up for services that they didn't request and MS tools will automatically confirm such signups.
Indeed it's a bad thing but how bad?
The admins of some web service get a database of emails, send them those registration links, make their mail software create the accounts and? They end up with a service with accounts that they could create without sending those emails, before they send some emails to solicit users to perform some action on their (long forgotten?) account. There is no additional threat unless I'm missing something.
The admins have only an extra thin layer of protection because of the confirmation step but I think that any court can see through it.
The exploitation and potential damage would be service specific. Say a Dropbox like service for computer file syncing: An attacker creates an account for 'alice@example.org' and gets the signup email automatically confirmed. The attacker uploads some malware files to the account. After some time Alice attempts to create a valid account and resets password for 'alice@example.com'. Then Alice installs a desktop file syncing client provided by the service and malware files from the attacker get downloaded to her machine.
Another example would be if a company hosted a web app for employees that allowed signups only from @company.com addresses. In such case an attacker could be able to signup with such an address.
You are right. I didn't think about 3rd parties creating accounts on a service they don't control.
It defeats the email verification entirely. If that weren't necessary for something, why would the site require it?
The link leads to a page where you need to press a button (HTTP POST).
As far as I know there’s nothing.
The alternative is to send an OTP in the mail and tell the user to enter that.
In that way there is no link to auto confirm.
However, if you do that ensure that you have a way to jump straight to the page to enter the OTP because (looking at you Samsung) the account registration process can expire or the app is closed (not active long enough) and your user is stuck
> These days there's also to consider that some Mail Threat Protection Tools (at least Microsoft Defender in Exchange Online does this) click links in Mails to check them.
What an insane policy, why am I surprised Microsoft came up with it…
It's not actually insane if the application hosting the link follows the principle that GET requests should not mutate state.
This problem is ~20 years old from when CMS platforms had GET links in the UI to delete records and "browsing accelerator" browser extensions came along that pre-fetched links on pages, and therefore deleted resources in the background.
At the time the easiest workaround was to use Javascript to handle the link click and dynamically build a form to make a POST request instead (and update your endpoint to only act on POST requests), before the fetch API came along.
It is insane because it brings literally nothing security-wise (an attacker can easily detect that the link is being opened from something else than an end-user's browser, and not deliver the payload) while actualy compromising the security of their users (by allowing an attacker to know which addresses exist and which do not, which is very useful if you want to attack companies).
It does not only show to attackers that your address exists, it also shows that it is hosted on Microsoft 365 and is ATP is licensed.
The idea is that the pre-fetching is done by an environment that looks similar to the end-user's browser.
I've had this problem as a user, accidentally previewing a link in iOS by tapping for too long.
This is even worse for copying the link. On iOS the contextual menu comes with the preview, which will destroy the magic link.
4. Make sure the sign-in link on mobile works with your mobile app.
When McDonald's switched from email/password to magic links I had a hard time getting the magic link to work with the McD app. It usually would just open in the McD website.
Thus was quite annoying because about 98% of the time I eat McD's I would not do so if I could not order via the app [1].
I finally gave up and switched to using "Sign in With Apple" (SIWA). There was no way that I could find to add SIWN to an existing McD account, so had to use the SIWA that hides the real email from McD. That created a new McD account so I lost the reward points that were on the old account, but at least I could again use the McD app.
[1] They have a weekly "Free Medium Fries on Friday" deal in the app available for use on orders of at least $1. Almost every Friday for lunch I make a sandwich at home and then get cookies and the free fries to go with it from McD.
McD app is the absolute worst.
1) rooted or bootloader-unlocked Android devices are not allowed (granted it's easy enough to get past it for now but the checks are still there). 2) 2FA requirements as if anyone would bother to steal coupons from others
It appears that they want ordering burgers to have the same level of enhanced security as banking apps. Not even crypto or trading apps bother to block unlocked devices in such a way. Blocking rooted devices doesn't even make banking apps more secure but for them I can at least understand the reasoning.
I have heard that you are basically paying double what you normally would if you aren’t hunting for deals in mcd’s app these days. How much truth is there to that?
A lot. MCD corporate seems determined to get on the user data gravy train, and appears to be subsidizing it for the franchisees.
Three large fries ordered at the counter costs over ten dollars.
It’s not about data, it’s customer segmentation. Frequent customers are more price sensitive, and are willing to use the app to get all the discounts, while occasional customers will not, so they can capture both the more price sensitive part of the market while getting higher margins from occasional buyers.
As someone who spent many years segmenting customers and generating personalized marketing offers -- McDonald's is awful at this. I was a 2-3x/monthly customer (USA based) for years (even more frequent a decade ago, but I'm talking about since the app), ordering the exact same core items every time (except during breakfast).
When they began "value meals" last summer (which don't include their flagship items) they also removed the best deals from the app, the ones that did include Big Mac, QPC, 10-nuggets. I've placed one non-breakfast order in 6-8 months, whenever they started this.
I'm just one person, but if a customer declines from an expected 15-20 visits over a half-year period to 1, and you don't adjust your offer algorithm (and you're the biggest restaurant company in the world so no lack of resources), something is seriously wrong.
Whenever this happens to me I keep wondering how much I am of the A/B data test where I'm in the "less important group". Is it possible that their changes engaged (or profited from) the more active (daily/weekly customers) by making your situation worse?
Perhaps. Let's assume that the value meals is a massive hit and they are collecting far more revenue from customers who like it, than they are losing from people like me.
That's the whole point of data analytics and personalized marketing - even if the value meal works for most people they can still go back to sending me the offers and promotions I responded to previously, in an attempt to reverse my recent decline in spend/visitation. The app makes it possible to send individualized offers. There shouldn't be an entire "B" group where they just say, oh well.
They used to have great deals on the app in Germany. I used to go to McDonald's all the time. The deals suck now, and now I only go if I'm really craving a McMuffin Bacon & Egg.
Whatever they're doing also isn't working for me.
> they also removed the best deals from the app
They've captured the user base with the money that corporate was pumping into the app deals, and are in the process of enshittifying it by transferring the value to themselves instead of the users.
This can work in a lot of industries - I am skeptical fast food is one of them. Switching costs are low, alternates are plentiful, and collecting information (reviewing deals/prices across companies) is relatively easy.
If McDonald's enshittifies its deals while continuing to raise prices, it's way too easy for loyal customers to go elsewhere. I'm saying this as a huge fan and extremely loyal customer of McDonald's for decades... they are at serious risk of losing people like me. As I stated, I've gone from 15-20 visits to 1 since last June/July, whenever they made the big change.
We've got similar opinions here. I'm just pointing out that the overall experience here feels familiar, and it wasn't until reading this thread that I really put it together.
I agree with you that I'd be surprised if Enshittification works as well here as it does in tech, but maybe since there's an app involved, they just think they can get away with it. Who knows.
Sure they want user data to observe people's purchasing habits. But they already have that if you always use the same debit or credit cards like most people do.
But the more people use the app, the less cashiers they need and the less ordering kiosks they have to install. Plus customer satisfaction goes up because you can order ahead and your food is ready when you arrive. And getting used to the discounts means you probably won't switch to Burger King or Wendy's.
I think additional user data is a relatively minor part of it.
> you can order ahead and your food is ready when you arrive
That just sounds like a great way to get cold McDonald's...
> I think additional user data is a relatively minor part of it.
You're probably right about that, but I've always undervalued user data because I don't think it's ethical to exploit people like that.
I'm sure that a well-timed push notification suggesting a personalized meal deal right around hungry-o'clock is the real goal of pushing this stupid app on their customers.
>> you can order ahead and your food is ready when you arrive
> That just sounds like a great way to get cold McDonald's...
The idea is to order 3 or 4 minutes in advance, not half an hour before...
> your food is ready when you arrive.
The food does NOT start cooking when you order it if you’re picking up at drive thru. It starts cooking when you pull up to drive thru and give the magic code.
In fact if the food is not easy to prepare you get put in a special parking space, where you wait for your order to be prepared. If it includes soft drinks they might serve those before they make you go park.
Disagree on not going to BK/Wendy's. The "deals" game becomes a habit, switching costs are basically zero, people start to comparison shop each app for the best deal (like shopping for air travel). It's a bit of work because there is no single consolidator but it only takes a few seconds to scan each apps offers.
At this point, being a fast food chain that doesnt have an app with deals is probably not viable - but I am very skeptical it generates any loyalty.
I treat food delivery apps the same way. There’s no stickiness for me, I just check all of them and pick the one with the best coupons for my restaurant. A sign that this kind of stuff is very much a commodity. I usually end up on DoorDash, but that’s mainly because the current credit card I use affords discounts for it and as a result wins in the bidding war for my business
> But they already have that if you always use the same debit or credit cards like most people do.
Don't they have only the last 4 digits and the issuer of the card? It is likely enough but there will be some noise.
Not to mention any potential legal trouble if they used the card details without explicit consent. App contracts will get around that.
They have your name too. From what I understand, the tracking is generally done via something like the hash of the card number though. I've never heard of any legal or compliance issues with that, since the card number itself is not stored.
Submitted a Subject Access Request to McDonald's here in the UK. I'll update here on progress.
> Three large fries ordered at the counter costs over ten dollars.
This is kind of hilarious and depressing but I live in a high enough cost of living city in the states and I order mcd’s rarely enough that I cannot tell contextually whether your statement indicates this is overpriced or underpriced.
It depends on how recently they came out of the fryer, how fresh the oil is, and the grease-to-salt ratio.
I will sadly admit that the high price of fries only angers me when they're not fresh.
> Three large fries ordered at the counter costs over ten dollars.
Ask for a “bundle box” next time you’re there. They’re usually named after a local sports team.
Two Big Macs, two cheeseburgers, two fries, and a 10-piece nuggets for $12-15 depending on the market.
I think retail for just the Big Macs is that much these days.
No app required.
That is an incredible amount of cooked calories for that price. No idea this was a thing. I do remember being in college and local mcd’s doing the typical “if team wins chicken nuggets are $5 for 20” but never heard of this sports box concept
Much more - most McD's in USA charge over $4 for a large french fries.
It depends on order size. I think orders for one or two people over time you'd save close to 50% between deals and using points. For larger orders 20% off once a day is about the best you can do. (I'm my area/experience.)
"Normally would" is more likely, prices from the mid-2010's. The order I used to pay about $12 and change for in 2015 (I know this because I ate there at least once a week), is now about $13, by using the app deals.
However since the rollout of "value meals" last summer, they took away some of the better deals and now McDonald's is simply expensive (for McDonald's) even with the app.
The difference isn’t nearly that dramatic, but there are definitely savings to be had via the app.
One thing I recently found annoying with Slack was that I wanted the company chat on my phone, but I didnt want the company’s email on my phone given the overly broad control of my phone
so I got the magic link on their computer and then I made a qr code
but wait, the email quarantine system had altered the whole link so I had to extract that
but wait the redirect url back to slack was malformed because of the url encoding and i had to fix that and then make the qr code
like wow just give me a qr code or code instead in the original magic link email!
Would it have worked to forward the mail from your work email system to your personal email?
If it’s a big corp, they probably have strict data exfiltration policies for corp email.
Maybe this one email would have been fine, but if it gets tripped, it’s not worth the headache.
These same corps have opinions on where users can be logged into Slack as well. And ffiw most enterprises that have this kind of device management don't allow login via magic links via email anyways.
Yes, accurate, I was able to access some slack workspaces but not the main one without putting the invasive management profile on my phone
It wouldnt have worked any differently from the first qr code with quarantine, and been a flagged violation, eventually
Now your private email contents are subject to discovery.
Assuming we are talking about discovery in a civil lawsuit involving your employer the party opposing your employer can ask for all documents you have that are relevant to the lawsuit. It is then up to you to turn over those documents.
If they specifically ask for documents that are not relevant or if their request is too broad so will produce a lot of irrelevant documents your company's lawyers will tell them no.
By the time someone is actually specifically giving you a list of things to turn over that includes your private email it will only be asking for things that are relevant. Most of your personal email will be excluded.
Genuinely: why? All that is related to the business email is already accessible, it's just been forwarded elsewhere. The info is already known. What's to discover?
To discover where else you then subsequently forwarded it.
I'm not suggesting this is actually a problem, but that's how an argument could go.
It indicates that you used your this other email for work purposes. The point is that they don't know what's in there, and they want to see if you discussed stuff relevant to the case. The judge will deny such a request as a fishing expedition if there is no basis for believing that you used your personal email for work purposes. But if it is discovered that you started sending work emails to that address...
One of the biggest advantages of magic links is that they're unphishable while still being easy to use (unlike passkeys).
Having a code completely negates that advantage, as attackers can just set up a fake website that asks for the code.
Magic links should log you in on the device you click them, not on the device that requested the login session. Anything else, while being a little bit less annoying, is a security issue and should be treated as such.
That would require I have my email on every device I might want to log in with.
I don't like that for a number of reasons.
The conventional password system requires you to have a shared password manager on every device or that your reuse or memorize passwords. And that none of the service's users reuse passwords.
It's all trade offs, else it would be easy.
I can access my password manager on my trusted device, and manually type in my password for whatever service on any other device. This is exactly what I do for the rare but important time when I need to login on a device I don't want to have total access to everything.
I see. Yeah, I pitch a scheme in a direct response to them where you can still let a magic link authenticate a session on another browser/device.
Not to mention passkeys, which people seem to be so enamored with.
When using magic links, you can still support the common UX polish of letting a user log in on a different browser/device.
If the user opens the magic link in the same browser that initiated the email, then just log them in. Otherwise, present them with the Apple-style "Do you want to authorize a login from 1.2.3.4 using Firefox on iOS possibly located in Portland, Maine? [Authorize] or [Reject]".
1 and 3 are mentioned in the article. It’s still annoying if there is no password option.
> For example, an iOS user might prefer Firefox mobile, but their email client may force the link to open in an in-app browser based on Safari.
Hey, wasn’t Firefox on iOS based on Safari related tech anyways?
https://en.m.wikipedia.org/wiki/Firefox
> However, as with all other iOS web browsers, the iOS version uses the WebKit layout engine instead of Gecko due to platform requirements.
I do agree with what you’re saying though! Just those two in particular will probably have pretty good compatibility, which I was amused to find out when I looked into it.
> Make sure the sign-in link can handle email clients that open links automatically to generate preview screenshots.
Any suggestions on what needs to be handled here? My first thought is UA checking to see if it looks like a real browser.
The link is a "safe" GET request. The page loaded via the link should do an "unsafe" POST for the login, via javascript with a form button for fallback.
https://www.rfc-editor.org/rfc/rfc7231#section-4.2.1
>The purpose of distinguishing between safe and unsafe methods is to allow automated retrieval processes (spiders) and cache performance optimization (pre-fetching) to work without fear of causing harm. In addition, it allows a user agent to apply appropriate constraints on the automated use of unsafe methods when processing potentially untrusted content.
Exactly the same for email unsubscribe links, or a one click "buy now" link.
If you want to do this without JS just add a page with a "Click here to complete login" button that does the POST.
Automatic link pre-fetchers know JavaScript too and will trigger your JavaScript to post.
I've had to implement a system where if the link was minted x minutes ago, the JavaScript on the landing page is disabled.
It's just another arms race. It shouldn't be this hard, but in email it seems everything is additionally harder to do.
Why not just have a username & password. Why make everything so complicated? We just successfully got password managers deployed to most users, only to drop passwords entirely for a subpar system?
One example is an unsubscribe link. Legally, it would be no bueno to have it behind any sort of login.
Another is just counting if a link from an email was clicked. I want friction to be as little as possible. That's done by having some sort of redirect, but you have to use a JavaScript initiated post to weed add false positives. That's already ridiculous, but because of automated link prefetchers, you still need to disable that and show a f'n button.
And then I have to answer to clients that want to know why their clickthrough stats are down precipitously and I don't honestly have the wherewithall to explain the inner workers of every filter that snoops their email before they read it.
> We just successfully got password managers deployed to most users
Source?
Every desktop and mobile OS has a built-in password manager perfectly adequate for this use case, with encrypted sync and backup capabilities.
In my app, I just added an “Almost there!” Page with a button that the user needs to click. I still need to add a fallback option that uses a one time code for the other reasons mentioned above.
Save a browser cookie when the login is initiated. When the link is clicked check if the same cookie is present. If not, ignore it. Expire the link and the cookie after n minutes.
Surely this breaks the "email is not on same device as login" use case? At least with normal magic links, they're merely incredibly annoying but doable (via e.g. typing in the URL)
- [deleted]
That use case still works. In fact it works better because if you click the link on your phone you don't automatically get logged in on your phone browser (or your email client's in-app browser). You can then copy the same link on your desktop and it will work as expected.
I'm confused. How do you get the cookie from the original device to the other device?
It's the other way around. You copy the URL to the device that has the cookie.
How do you copy the link between devices? QR code?
As long as you also have a code to enter, then things will feel fine across devices.
After reading the other replies, this seems like one of the more effective approaches. Thanks!
Using a time-based expiration rather than a usage-based expiration should help
E.g. require to click a button to actually sign in, don't consume the token and establish the session on mere URL access.
Is 3 even possible?
[dead]
3 isn't really possible, because the redirect needs to take you back to the browser session where you initiated the login from.
It definitely does not.
Have your logging-in session wait for / poll "has visited magic link", and authenticate that session when it's done.
Tons of systems do this. It works great, and it can quite easily work without any web browser at all on the logging-in side because it just needs to curl something -> poll for completion and save the cookies -> curl against the API. A number of oauth flows for e.g. TVs work this way, for instance, because it's a heck of a lot easier than integrating a full browser in the [embedded thing]. Many app-based 2FA (e.g. Duo) works this way too.
So I misclick a link in my email client and the evil guy who requested in is now logged in on his browser god knows where? Surely that can’t be real. It sounds awful. TVs involve copying a code to make sure the right device is being authenticated, or the ones I’ve used have at least.
Duo 2FA works the same way. In principle yes. And it's basically always accompanied by a "click this link" -> "are you trying to log in, and is this you? yes/no" page to resist that.
Small code copying is also a very good answer though, yes. Roughly as easily manipulated, but nothing's perfect, and it's less "I didn't mean to click that button"-prone.
Yeah but I routinely click links in emails whereas logging in is the sole purpose of Duo. I could easily just intend to scroll the page and end up tapping the link.
so have that open a site that says "confirm login? y/n".
I don't mean to imply that just visiting the link should be enough to complete a login. That's a GET and there's a LOT of issues with doing anything important on GET. Just "do something on a different machine, then automatically complete login on the one logging in", and magic links to trigger that flow are a rather straightforward option.
There's no reason at all that it has to all occur on the same machine, and many reasons why attempting to require that doesn't work out in practice even when it does happen on the same machine.
Ah I see. Yes, that makes sense.
This seems dangerous:
1. Attacker starts a log in and triggers a magic link email 2. Email received and my browser client previews the link without my desire 3. Attacker is now logged in
That’s why you combine it with a check for source IP and tell your user that they need to approve from a device that has same IP as the one they are logging in on. So if I’m logging in on my laptop, and approving with my phone, it will be rejected if my phone is using mobile data while my laptop is using landline, but will approve if my phone is connected to WiFi of the same network my laptop is connected to, or if my laptop is tethered via my phone, because then I have same external source IP on both devices.
This scenario is a solution only in simplest cases. It doesn't work when someone routinely uses a VPN on the phone (when often uses free public wi-fi in airports, railway stations, markets etc) because of possible MITM attacks.
also some ISPs will give you a different IP every request
This has security and usability issues. NAT/CGNAT means a potentially large number of people can hijack your login.
The links are one-time use so you need to take this into account anyway or users simply can't login. It's usually done with a required button click after following the magic link. Or you can try JavaScript techniques to detect a real browser.
No "tons" of systems do not do this. If you come across one that does it was built by a team that has no idea about security.
TVs etc. are special cases because obviously there is no way to redirect to them, and even there developers will always have some kind of secondary checks like having you enter a code displayed on the screen.
When I sign on to a bank it sends an SMS. Then my phone prompts me to share that code with the brower, on my desktop. It's a neat QOL "feature" - but kinda feels too automated to be secure.
That's because the server recognizes both clients, and you are prompted to approve the other client from the client that has the code. You are giving permission to the remote client, not taking permission from the remote client.
The server recognized my device from the messenger/SMS app? That seems not correct.
But somehow, the desktop browser and my mobile are tied together for this app. But no other sites have this magic.
If you have an iPhone and a mac, most sites that use SMS OTPs work this way
Linux desktop, android phone.
I've come across dozens.
Google does it. Paypal does it. Duo does it. Lots of single-sign-on systems do it. All of those including not-TV scenarios, just normal computer-and-phone stuff, as well as sometimes other weird flows. Many of these are far beyond what most would label as "security competent", into "login security is a large part of their business and they have significant numbers of specialists hired".
(it is probably safe to say none are "truly secure" or "actually security obsessed", but I doubt that's actually possible in large quantities. the requirements are too steep, for both implementers and users.)
It's not the most common, certainly, nor anywhere close. But it's very far from nonexistent.
Where does Google do this?
Log in on browser -> push notification "is this you?" on your phone -> browser automatically continues when you say "yes".
But that's only as a second factor right?
Is that materially different? It's a login that's completed on a different machine, and automatically resumes on the intended one.
I might receive a magic link on my phone but then sometimes I'll copy/paste that over to my desktop or another device.
This works on 99% of magic links I've tried except for cases when they are trying to prevent account sharing. I remember the Bird bike app did this, where they required the magic link to be clicked on the same device login was initiated on. I was using my friends account and he would just forward me the link until one day this stopped working.
It seems like “prevent account sharing” and magic links are somewhat at odds by design.
The idea being the user(s) would then have to share a email inbox to share logins, not just a password. It might not be the most inconvenient - this is partly how Netflix did their "Household" lockdown. You can request a travel code and this gets emailed to the primary email.
I feel the way Netflix did this broke the social contract of profile sharing on purpose - before, if you were a good tenant, you could freeload off another paid account without inconveniencing them at all. Memes and jokes formed of still being on an ex-partner's account or how people would rename themselves "Settings".
Getting an email and being harassed for the code by all those account sharers? Much more open and open for annoyingness.
More than a shared password?
Not necessarily, some services would have the magic link verify the session that triggered it regardless of browser or device.
I assume it generates a session on the post-login screen and authorize that session upon accessing link
That has the problem of opening up an attack where the attacker requests the sign-in link, the person receiving the link blindly clicks it, and the attacker now has access.
People blindly click links all the time. It would have a low success rate, but would be more than 0%.
We've been using Magic Links for a few years (and yes, one reason was to avoid the security issue of storing user passwords when we were just at MVP stage) and found the top problems with it are:
1. Some users (0.1%) just don't ever get the email. We tried sending from our IP, sending from MailGun, sending from PostMark, having a multi-tier retry from different transactional tools. Still, some people just will not ever be able to log in.
2. People click old Magic Links and get frustrated when a 6-month old link "doesn't work". We've decided to remedy that by showing them a page that re-sends the link and explains the situation (like Docusign does) instead of an error message.
3. People will routinely mis-spell their email and then blame the system when they don't get the code.
All of this still results, I feel, in way fewer support tickets than the email+password paradigm, so I'm still in favor of Magic links.
It's indeed interesting the number of people misspelling their email address, or having an inbox so full that it cannot receive emails anymore.
I never tried to add magix links, but I added Google Sign in to my SaaS several month ago, and since then, it accounts for more than 90% of new sign-ups (users are devs, so rather tech savvy and privacy aware). I'm now convinced that no other method is a priority (I still have email/password of course).
> but I added Google Sign in to my SaaS several month ago, and since then, it accounts for more than 90% of new sign-ups (users are devs, so rather tech savvy
I do it for services I don't care about. In my mind it is more privacy for me. Keeps you out of my real inbox and my password out of your system and I believe that I can - to some extend - remove myself without having to go through whatever crap account deletion process that services has tried to cobble together.
Worst offenders let me login with google and then immediately asks for name and phone number or email and asks me to verify it.
> my password out of your system
This shouldn't be a factor because your password should be a random series of characters that are unique to that site.
> I believe that I can - to some extend - remove myself without having to go through whatever crap account deletion process that services has tried to cobble together.
To an absolute minimal extent: you can make it so Google won't tell them whatever it was they already told them again. But you can't make them delete the data that they already lifted from your Google account.
For keeping surfaces out of your inbox, that's what email aliases are really good for. Register with an alias and then block that alias if they abuse it.
Wouldn't privacy aware users prefer passkeys or passwords, instead of any kind of SSO?
In general, I do understand that use of SSO is due to convenience. Especially since in many cases websites provide less friction when signing up via SSO instead of using username+password.
Believe it or not, most users are not that privacy cautious
That would be my guess too. I think convenience always win.
I have my HN username at a venerable webmail service. I check it about once a year, tops. My name isn't unimaginably rare, but neither is it "Smith".
I am shocked, shocked, by the number of different K. Strauser people who have typed that email address into some random website or another. I've gotten bank notifications, loan documents, Facebook signup info, meeting minutes from some random volunteer work, and all kinds of other things. When I can figure out from context who the intended recipient is, I try to let them know so they can fix it. On one occasion, the person sent me back a swear-laden diatribe for "hacking their email". Sigh.
I think this has made me a better engineer, though. When someone says something in a meeting like "...as long as they type their email correctly", I can jump in and address that myth head-on. No, people will not type it correctly. If it's a minor pain in the neck for me, with an uncommon name, I can only imagine the traffic that the world's John Smith's get.
Same issue. I've had university professors put my email address in their sylabus instead of ____.edu, and been carpet bombed by assignments, excuses, and pleading diatribes.
I'm listed as the email address for _many_ utility bills, doctors offices, and more political campaigns than I can count.
Comical how many people mess up their own email address.
I just don't get it. A legitimate typo I can see, sure, but so many of the things I get looks like someone said "email address? I guess I can just pick one!"
The number of support requests I got last year because of [hotmail|gmail|msn|yahoo].con > 30
I just auto switch any incoming .con to .com on the back end. 100% of the time it is a user typo
Nice trick! I check on the frontend for all gmal, gmial, etc variations :)
> I check on the frontend
This is the way. The user can benefit from feedback that they got something wrong, in addition to a helping hand.
Just a very small detail, but want to point out the distinction between these two comments. "Revicon" is demonstrating 10x thinking, it's not about being better at rewriting a linked list algorithm or some leetcode challenge.
Player 1 gets the same support request over and over, does nothing about it, ("hey, that's what the user entered, they should be more careful!"), complains about it online, and who knows how many hours are wasted in the back and forth with the customers.
Player 2 simply makes the necessary change on the backend, the users don't even realize they made a typo, totally seamless flow.
Hat tip to you. Hope you screenshot these two comments and bring this up in every interview to exemplify the contrast between "technically correct" and high-efficiency problem solving.
A tasteful post and distinction well highlighted. Humorously, Yvo Schaap is no stranger to 10x thinking. For one thing, Yvo publishes diagrams on SaaS/dev topics that always seem consistently way ahead of their time in terms of their organization and completeness.
A couple of years ago I think I saw a frontend library that warned the user / auto-fixed those typos, but I can't remember its name, and all I can find now are SaaS offers for that kind of service.
Which I'm not entirely enthusiastic about as it leaks all user emails to some random service.
Magic links can be very useful, but for some users the issue is in only supporting magic links.
Funny part is most of those apply to passwords too, using an old password and complaining its not working, mistyping shit and complaining that its the system, and requesting a password reset and not getting the mail LOL so i only see upsides
... but the usability is a nightmare.
Absolutely. Users have to wait for the email before signing in, it does not work on devices without email without copying the link, etc.
Email should not be considered a secure channel.
Username+password (or passkeys) with a password manager (which ensures that credentials are used on the correct domain) via HTTPS is probably the only end-to-end encrypted way of exchanging credentials with good UX for general public.
With password reset, you are also trusting email.
Even with passkeys or TOTP 2FA, we've decided email is the root, for better or for worse (for people with gmail, it's likely better than SMS would be on a crappy carrier, but it depends on so many factors, including how many hundred apps have Gmail read access via OAuth...)
If you are storing sensitive information in the system, by all means, you should act accordingly and require higher-security login than magic links. But if you do, you really should not be accepting username+password either. You need to at least put some 2FA on there to step up one level of security. And not SMS- or email-based 2FA either.
90% of web apps don't handle that kind of information, and for them a magic link is at least as good as passwords (as this article explains). Those that do handle things like personally identifiable information (beyond an email address) really should be enforcing 2FA or proper electronic IDs.
There is a whole profession writing recommendations about information security, and every web developer needs to be able to do this kind of analysis at a rudimentary level. We don't need to wing it, we can analyze security requirements in a systematic way.
Also what's the reasoning behind not wanting to store passwords?
It's not like the rest of the customer's data is not valuable? If you don't feel comfortable storing passwords, the amount of data I'd trust you with is strictly zero.
No, kudos to them for looking at a piece of data and asking themselves if it's worth storing—more companies should do that with more data. It's not that the rest of the data isn't valuable to some extent, it's that every piece you have makes the blast radius of a leak that much bigger, so why hold stuff you don't need?
Planning for a breach doesn't make you more likely to have one—if anything it makes you less likely!
To be fair to 404, they're trying to limit the amount of data they hold which IS good, but in the end they need to have the email address of subscribers.
In my country even the social security number of people is public information.
The UX debate is valid, but magic links (and emailed one-time codes) are clearly more secure than password + password reset. Control of the email account gets you in either way. Passwords are an additional attack vector.
I've been a loyal Mercury customer for a while now, but their forced use of magic links as a third authentication factor any time my IP address changes (after authenticating with a secure password from my password manager and after a valid TOTP) has me ready to move my company's banking elsewhere.
I could understand requiring a third factor to authenticate if signing in from a different location or a different ISP than I've been using for the past 5 years, but it's ridiculous to do so if nothing has changed (except the final octet of my DHCP-assigned address) since I last signed in yesterday. I use a different computer (via SSH) to read my email than I do for web browsing, and cutting-and-pasting a signin link that's hundreds of characters long (spanning multiple lines in Emacs, so I have to manually remove \ where it crosses line boundaries) is a PITA.
Adding friction on every sign-in colors all subsequent interactions I have with an app, and makes me hate using it.
I’m the CTO of Mercury
You shouldn’t get the device verification requirement if you’ve used the device before (we store a permanent cookie to check this) or for the same IP. Any chance your cookies are being cleared regularly?
We added this after attackers created clones of http://mercury.com and took out Google ads for it. When customers entered their password and TOTP on the phishing site, the phisher would use their credentials to login and create virtual cards and buy crypto/gold/etc. The phisher would also redirect the user to the real Mercury and hope they figured it was a blip.
This device verification link we send authorizes the IP/device you open it on, which has almost entirely defeated the phishers.
Since WebAuthn is immune to this style of phishing attack, we don’t require device verification if you use it. I highly recommend using TouchID/FaceID or your device’s flavor of WebAuthn if you can—it’s more convenient and more secure. You can add it here: https://app.mercury.com/settings/security
That said, we are talking internally about your post and we do recognize that as IPv6 gets more traction IPs will rotate much more regularly, so we’ll think if we should loosen restrictions on being a same-IP match.
Yes, I clear cookies every time I close my browser, as a layered approach to privacy on top of uBlock Origin and NoScript. There isn't a great way to exclude certain sites from this, other than setting up a dedicated web browser in a container just for Mercury.
I wasn't aware that WebAuthn didn't have this requirement. I prefer TOTP because I actually like having a second factor in addition to a credential stored on my computer's hard drive (whether a password or a private key in my password manager), but I might be willing to reduce my security posture to get rid of this annoyance.
One suggestion: the link would be half as annoying if it was easily cut-and-pasteable rather than a long email-open-tracking link spanning multiple lines. This is what it looks like when I copy it out of my email:
I have to manually remove the backslashes and re-combine the lines before pasting into my web browser.https://email.mg.mercury.com/c/eJxMzs1u4jAUBeCncXZB9vVfvPACZshoWIwYoiasdgkra2KV_JCGqPTpK-imq7xxx40vlO9IKia6ggL6zUlQHObdF6\ JI0alRHBWQvWKRuD4loLZxsJSRXZAwfNBQeQWozasdgeWsMyFZozE4RKZ4d151NOFtuq9w6IqLb-d5fGdyzaBmUIdx_NkzqBeacrqXkZaMxGSNQyQmf7_9GW7\ Hf1cJ8zW9TshAwwba3ccLuN3u_r_PR9j_GkxxxmadDu32c59jMfkYFmKKP0baIT0vzP4ynHN_-yyhZOTy9jmPPQn6gL-VLMfvvIA_XxbywRYhUbZUp0RpVCUC\ qDsbasJHeObFMZ4YrFw1cAAAD__4XPZXwEdit to add: looks like email.mg.mercury.com is hosted by Mailgun. Are you intentionally sharing these authentication tokens with a third party by serving them through this redirect? Do your security auditors know about this?
I set Firefox to delete cookies at shutdown, and also an add-on called Cookie AutoDelete, but they both have an option to whitelist a site.
> I wasn't aware that WebAuthn didn't have this requirement. I prefer TOTP because I actually like having a second factor in addition to a credential stored on my computer's hard drive (whether a password or a private key in my password manager), but I might be willing to reduce my security posture to get rid of this annoyance.
I've seen passkeys support something like what you're after. The browser will produce a QR code you scan with your phone, and then you authenticate with the passkey via the phone, which then authorizes the original browser.
I'm not absolutely certain that this is part of the spec or how it actually works. I'd like to know. It solves a couple different usability issues.
You could always use something like a Yubikey.
> You could always use something like a Yubikey.
This is the option I prefer, but only on sites that allow me to enroll more than one device (primary, and backup for if the primary gets lost or damaged). AFAICT, Mercury only allows a single security key.
I have an encrypted offline backup of my TOTP codes, so if I drop my phone on the ground, I don't get locked out of all my accounts. I keep this separate from the encrypted offline backup of the password manager on my computer, and as far as I know, neither has ever been uploaded to anyone else's "cloud." Malware would have to compromise two completely separate platforms to get into my accounts, rather than just iCloud or whatever credentials.
I understand the desire for phish-proof credentials, but—given that I don't click links in emails—my personal threat model ranks a compromised device (via attack against a cloud service provider, or software supply chain attack against a vendor with permission to "auto-update," or whatever) much higher likelihood than me personally falling victim to phishing. I readily admit that's not true for everyone.
> my personal threat model ranks a compromised device ... much higher likelihood than me personally falling victim to phishing
I completely understand that. I'd actually be interested in reading anything practical you might have on that topic if you don't mind. I asked some experts who gave a talk on supply chain security last year ... they didn't have a lot of positive things to say. Developing software feels like playing with fire.
It feels unstoppable, which is why the best I can do is try to mitigate its impact. Some mitigations that come to mind:
The development environment where I'm downloading random libraries is on a completely separate physical machine than my primary computer. I generally spin up a short-lived container for each new coding project, that gets deleted after the resulting code I produce is uploaded somewhere. This is completely separate from the work-supplied machine where I hack on my employer's code.
On my primary computer, my web browser runs in an ephemeral container that resets itself each time I shut it down. My password manager runs in a different, isolated, container. Zoom runs in a different, also isolated, container. And so on.
Wherever possible, I avoid letting my computer automatically sync with cloud services or my phone. If one is compromised, this avoids spreading the contagion. It also limits the amount of data that can be exfiltrated from any single device. Almost all of the persistent data I care about is in Git (I use git-annex for file sync), so there's an audit trail of changes.
My SSH and GPG keys are stored on a hardware key so they can't be easily copied. I set my Yubikey to require a touch each time I authenticate, so my ssh-agent isn't forwarding authentication without a physical action on my part. I cover my webcam when not in use and use an external microphone that requires turning on a preamp.
I try to host my own services using open source tools, rather than trust random SaaS vendors. Each internet-facing service runs in a dedicated container, isolated from the others. IoT devices each get their own VLAN. Most containers and VLANs have firewall rules that only allow outbound connections to whitelisted hosts. Where that's not possible due to the nature of the service (such as with email), I have alerting rules that notify me when they connect somewhere new. That's a "page" level notification if the new connection geolocates to China or Russia.
I take an old laptop with me when traveling, that gets wiped after the trip if I had to cross a border or leave it in a hotel safe.
I have good, frequent backups, on multiple media in multiple offline locations, that are tested regularly, so it's not the end of the world if I have to re-install a compromised device.
> The development environment where I'm downloading random libraries is on a completely separate physical machine than my primary computer. I generally spin up a short-lived container for each new coding project, that gets deleted after the resulting code I produce is uploaded somewhere. This is completely separate from the work-supplied machine where I hack on my employer's code.
Something like VS Code remote dev with a container per project? Just plain docker/podman for containers?
> On my primary computer, my web browser runs in an ephemeral container that resets itself each time I shut it down. My password manager runs in a different, isolated, container. Zoom runs in a different, also isolated, container. And so on.
Qubes, or something else? I've been looking at switching to Linux for a while, but Apple Silicon being as good as it is has made making that leap extremely difficult.
Mostly Linux with systemd-nspawn, also some Kubernetes, plus the occasional full VM. (If I were setting this up from scratch, I'd probably try to figure out how to run my desktop as 100% Kubernetes, using something like k3s, but I don't know how practical things like GPU access or Waypipe forwarding would be via that method.)
I live inside Emacs for most things except browsing the web, either separate instances via SSH, or using TRAMP mode.
If you switch to Linux, I highly recommend configuring your browser with a fake Windows or MacOS user agent string. Our Cloudflare overlords really, really hate Linux users and it sucks to continually get stuck in endless CAPTCHAs. (And doing so probably doesn't hurt fighting against platform-specific attacks, either.)
> AFAICT, Mercury only allows a single security key.
We allow multiple security keys. You can add more here: https://app.mercury.com/settings/security
Oh, nice! This wasn't obvious from the help text. Maybe add it to the FAQ on the "Adding security keys" sidebar?
Is there a reason that TOTP cannot be used as a second factor when using Passkeys?
Not sure why we suddenly went from 2 factors (password + TOTP) to 1 factor (passkey), even if passkeys themselves are better.
TOTP should at least be an option for the users.
You have to send emails through third parties or people won't get them, because you are also always sending them to third parties who host the recipients email and manage their spam. It might be a good reason not to send magic links but here we are talking about a tertiary confirmation, so its useless on its own right?
The link in the email could be a direct link to Mercury's website, rather than one that passes through a third-party HTTP redirect service.
Authentication tokens (even tertiary ones) usually are supposed to have pretty strong secrecy guarantees. I've done multiple security audits for SOC, PCI, HIPAA, etc., and in every case the auditors would have balked if I told them signin tokens were being unnecessarily logged by a third-party service.
(Also: I strongly disagree that the only way to get reliable delivery is via a third-party email service, especially at Mercury's scale, but that's a digression from the topic at hand.)
Oh good find, the link going through Mailgun as a redirect is a recent regression. We have a PR to fix that going live soon.
That said, our security team and I agree there is no security issue here. Mailgun already can see the text of the emails we send.
How is there no security issue here? Email is not secure and it's even less so when you are sending it via a 3rd party. If this were a photo site or something that would not be a big deal but we're talking about a bank. SMS is not much better. Like somebody said elsewhere in the thread, you should allow people to opt out of insecure third-factor verifications since they are just an annoyance and are ultimately security theater.
The emails in question are a third factor, not a magic login link.
Even if they were, almost all email goes through third parties which are trusted implicitly. That's not great, but email is the only federated system in existence capable of implementing this type of decentralized login at scale.
Maybe someday we'll be able to use something like Matrix, Fediverse OAuth, or ATProto OAuth instead, but those are all a ways off.
It's not security theater. He explained above how this is used to defeat a specific phishing attack that they've actually seen in the wild. There are other, different threat vectors (e.g. compromise of the mail server) that it doesn't prevent. But that doesn't make it theater. as it does provide other value.
What does it stop? You already did a 2FA at this point. If an attacker has my 2FA he most likely already has my email so the 'value' being provided is at the cost of more complexity for the user. If this adds value then why not also do an SMS as well to be really, really sure that the user is legit? That would add even more value.
And again, I wasn't saying that you can't do all of this nonsense, but users who see it as nonsense should be able to turn it off.
Again, see the post by MaxGabriel at https://news.ycombinator.com/item?id=42629109 where he explains how this measure actually defeated that particular pihishing/MITM attack.
The attack wasn't that the attacker has my second factor, the attack was that the attacker tricked me into verifying a single login/transaction using my two factors, on their behalf.
They probably judged that the inconvenience of the verification email affects few enough users that it is worth it. Most users don't switch IP addresses very often. And those that do, probably don't all clear their cookies after every session.
Adding SMS in addition to email would be obviously useless, as you point out.
Why would the attacker having your Mercury TOTP mean they most likely have access to your email?
Because my TOTPs are all stored in the same device and in my imaginary scenario they have that.
> passes through a third-party HTTP redirect service
The vendor might not be the only party to use an HTTP redirect service too! My email goes through a security screen by $EMPLOYER, which also rewrites links to get processed through their redirect service. Sure, it's for company-approved reasons, but it's still another party that has access to the login token.
At the very least, you can be creative with workarounds for such issues. A bookmarklet can be convenient.
javascript:void(window.location.href = window.prompt().replace(/\\\n\s*/g, ''));So you are intentionally crippling your browser and ability to access email (you need to ssh to another computer and access via terminal). You also aren’t able to handle emacs wrapping of long lines. And you are complaining that the security in place to prevent stolen credentials is “inconveniencing you”.
Pretty sure that is eMacs formatting, not the email itself? Can you kill-copy the URL?
What would be a more secure (yet reliable) method for email delivery for such emails?
Make the link in the email https://mercury.com/something instead of https://mailgun.com/something (which then redirects to https://mercury.com/something). Or (in addition to, or instead of, a hyperlink) provide a 6-10 digit numeric or alphanumeric code that could be copied out of the email message into a form field on the signin screen.
> 6-10 digit numeric or alphanumeric code that could be copied out of the email message into a form field on the signin screen.
To be clear this is what we're trying to avoid. An easily typeable code like that can be typed into a phisher's website.
How about giving me a setting to disable device verification: "I know how to type mercury.com into the URL bar and accept all risk of getting phished."
I appreciate you guys are trying to protect people, but no other financial institution I deal with requires this level of annoyance, and at some point I'd rather switch to a less "secure," but more usable service.
(I put secure in scare quotes, because some suggestions, like trading true 2FA, where I have two separate secrets on two separate devices, for a single WebAuthn factor, are actually accomplishing the opposite, at least for those of us who don't click links in emails and don't use ads on Google for navigation.)
Edit to add: or maybe save the third factor for suspicious activity, such as "new device adding a new payee," rather than every signin. It's been months since I onboarded a new vendor, and I'd be OK with only having to do the cut-and-paste-the-link dance a couple of times a year, rather than every single time I want to check my balance.
My understanding (as CEO of a startup using Mailgun for magic links) is that you're seeing mailgun in the URL because they have click tracking enabled — which, to be fair, is not super useful in the case of verification emails.
They could use a custom subdomain for this click tracking and "hide" the mailgun url from you, but we're finding that for some reason Mailgun doesn't just use a let's encrypt certificate, so some users will complain that the tracking links are "http" (and trigger a browser warning when clicked).
Anyway, even with click tracking disabled and links going straight to mercury.com, the security issue would remain the exact same (since Mailgun logs all outgoing email anyway).
But my understanding is that the contents of that email and its link do not provide "login" capability but "verification" capability. As such, a Mailgun employee accessing your data, or an attacker accessing your Mailgun logs, would only be able to "verify" a login that they had already initiated with your password AND your OTP —which means that's effectively a third hurdle for an attacker to breach, not a one-step jump into your account.
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> IPv6 gets more traction IPs will rotate much more regularly
unfortunately, only few ISPs do IPv6 correctly by assigning a fixed prefix to customers. most of the ISPs apply the ipv4 logic when adding ipv6 planning hence this situation.
hopefully this will improve in the future and more stable prefixes will be given to users.
I like the schemes that send a numeric verification code that you manually type in without an email link. can also use a text message. Maybe allow this to be configured.
security = 1/convenience
but also vice versa
- [deleted]
I think this is really great as a response to 404's post last week. I love 404 but I'm as annoyed by Magic Links as OP for the same reasons they mention.
Ricky Mondello wrote a really great blog last week[1] about how passkeys, as OP alludes to at the end, can be used alongside Magic Links, that I think is worth a read.
[1]: https://rmondello.com/2025/01/02/magic-links-and-passkeys/
I haven't had these specific issues with magic links specifically, but I do remember when Epic launched the Epic Games Store and they would e-mail you two-factor codes to log in. I consistently had issues where I wanted to log into their store, got prompted to enter the two-factor code they e-mailed me, got no email for several minutes, requested another code, didn't get that either, gave up and did something else, and then got both codes 30 minutes later.
The fact is that even in the best of times, e-mail isn't reliable. Things go to your junk folder. Links get blocked by work spam filters. Mailboxes get full (I assume? it's been a while).
Personally, I have my e-mail on my iPhone and anywhere else (work laptop or gaming PC) I have to log into icloud.com to check my e-mail; it's cumbersome. Let me put in a password. Let me scan a QR code like embedded devices do. Give me at least one other option.
Thank you, this is a better piece than TFA! Reading TFA I was rather confused at how passkeys are an alternative to magic links—it makes a lot more sense to view them as a complement. Magic links allow you access to passkeys, which are basically "Remember this Computer" on steroids.
Thanks for that link, I had not seen it and if I had known Ricky Mondello had written that, I probably wouldn't have bothered.
I'm still used to Apple people being almost completely invisible publicly.
I'm confused, what's going on here? Is there a reason you wouldn't have bothered reading a post from that specific person?
I meant Ricky’s post is great and if I had known about it first I might not have written mine! Added a link to it at the bottom of mine.
Ahh! Thanks for clarifying!
thanks for writing what you wrote -- I think it's important that we have this conversation as broadly as we can
Am I misunderstanding something, or are passkeys not actually an alternative to magic links?
Every implementation of passkeys I've seen has presented me with the option to create a passkey after I've already logged in with some other method. I'll admit that I haven't dug into it deeply, but the UX I've been presented with consistently makes passkeys appear to be an alternative to the "Remember this computer" button, not to passwords in general. Somehow the service has to know that this new device is authorized. I know depending on the provider there's such a thing as passkey syncing, but that doesn't solve the problem of getting the initial authentication done.
The key insight with magic links is that your security system is no stronger than its recovery mechanism. We are never going to get to a world where passkeys are treated as the only authentication mechanism—there will always be a recovery mechanism, and in most cases an automated one via email. Given that that is the case, magic links simplify things by just not pretending that we have a more secure layer on top. By making the recovery mechanism the primary means by which you interact with the authentication flow you're being more honest about the actual security of your auth system.
Edit: filmgirlcw has a link to an article that is much better than this one that explains how the two actually complement each other: https://news.ycombinator.com/item?id=42628226
I think as Ricky wrote last week [1], they should augment Magic Links or other auth methods. There are some positives about Magic Links for sure (though I don't know if making your email an even stronger attack vector is necessarily one of them), but for people who use a password manager, for example, they are a definite friction point that I think passkeys most certainly could alleviate.
There are definite UX problems around passkeys that could be improved and I think exporting will make syncing across systems a lot better (one of the reasons I use 1Password as my primary password and passkey system is so I can use my passkeys across devices; of course it helps that my employer uses 1Password as our system so I am logged into my personal and enterprise accounts and can auth then from personal or work devices, provided additional auth or enrollment isn't needed) -- but if the problem as 404 defines it is that they don't want to be responsible or even have to worry about storing your passwords/auth controls, I think passkeys is at least better for a subset of users than Magic Links.
But again, like Ricky, I don't think it should be viewed as either or. It should be both.
[1]: https://rmondello.com/2025/01/02/magic-links-and-passkeys/
Thank you for the link! I saw your other comment and actually edited mine to point to that, because it's definitely the answer to my question!
> though I don't know if making your email an even stronger attack vector is necessarily one of them
I'm unconvinced that magic links do make your email an even stronger attack vector. Essentially every service that would be inclined to use magic links would already have a way to reset your password entirely once the email is compromised. All magic links do is make this the primary way to interact with the auth flow.
The bad guys already know that your email is the best target. Magic links just make that very explicit.
>The bad guys already know that your email is the best target. Magic links just make that very explicit.
That's a good point. I guess my rationale is that it being explicit makes me feel less comfortable for my parents/non tech-savvy friends, who already may not follow best-practices for email hygiene (and may not use email providers that enforce stricter hygiene like 2FA or other methods of protection) and thus, systems like this, make their email even more explicitly the ultimate place to go for access to stuff.
>feel less comfortable for my parents/non tech-savvy friends, who already may not follow best-practices for email hygiene
making people feel less comfortable is probably a good thing.
i've managed to convince my dad to start taking his email security more seriously by reminding him a few times that if somebody gets access to his email, they can reset his password on every site where he uses that email address. it's good to remind people of why email security matters, and that it's not just about the personal messages from friends.
> Essentially every service that would be inclined to use magic links would already have a way to reset your password entirely once the email is compromised
Well, don't do that.
Do you have an alternative proposal for letting users back into their accounts when they inevitably lose their passkey? Because if you don't, this isn't a serious answer.
Password, not passkey. Recovery codes should be setup on account creation, but recovery of the password manager itself is what is required, and that usually has its own recovery mechanism.
Social key recovery is an underutilized solution as well.
How do you do account recovery when you lose a password or MFA token?
Of course, any website's auth system is as weak (or strong) as their recovery process. Different sites will implement this differently.
Typically by email, which OP says "don't do".
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> There are some positives about Magic Links for sure
Like what? I'm failing to come up with a single benefit (for the user).
Not needing to remember passwords or use a password manager.
Password managers are now built into every operating system / browser, with trusted encrypted sync capabilities. The UX of using the built-in password manager is better than that of a magic link.
Passkeys are in a transition period right now. There is no reason you have to have an alternative login method if you are using Passkeys, but no service has switched over to being Passkey only yet. Some users on older OSs / Linux might not be able to generate and store Passkeys yet, many users are not using a cross platform credential manager so if you've created passkeys with iCloud Passwords, there isn't a way to log in via linux right now.
Give it a few more years and I suspect we will start to see services start with creating a passkey and never collecting a password. The passkey portability specs will be implemented, and hopefully Gnome/KDE implement passkey support.
What does the final end state of passkeys look like? What happens if I lose the device I created the passkey on, if it gets bricked, or if I get banned by the platform that was supposed to be syncing my passkeys?
Passkeys are essentially an API for logging into websites that requires a password manager to use. The end state is that we become completely dependent on our password managers. To avoid a single point of failure, hopefully you own multiple password managers, and they’re on independent devices, and there is a way to sync them.
I'd think it's exactly the same as using a password manager. Yes in theory you could memorize 500 unique passwords or write them down, but no one is doing that.
There are a few things unique to passkeys though. You can register multiple passkeys for the same account so you could in theory have a physical USB key and cloud synced passkeys. Not many people would do this I would think though it would be easier than memorizing every password. There are also data portability specs in progress right now that let you export/import passkeys between services.
But at the end of the day I would suggest that it should be straight up illegal for a company to freeze your account without letting you export your data. It probably actually is by the GDPR. This problem also already exists for email too. If Google bans you, you'll find a lot of your accounts become unusable. Anything with email OTPs wont work, and some services like Discord won't allow updating your email without access to the existing one.
It can't be the same as my password manager if email password reset flows disappear. If I lose access to my password manager but not my email, then I can go through and systematically reset all of the accounts that I remember exist. What you're describing with passkeys, though, would not allow me to do that.
> But at the end of the day I would suggest that it should be straight up illegal for a company to freeze your account without letting you export your data.
This would be great but it only addresses the least likely failure mode out of the ones that I brought up.
And note that in many cases we're currently better off under the existing system if Gmail does ban you than we would be in your proposed world: only services that send OTPs on every login would be immediately inaccessibile, so you'll have time for most services to log in and switch to a new email address.
I think for most services you'd still be able to email reset your passkeys unless it's a particularly sensitive service, the kind which don't allow email resets of your 2FA tokens today.
A password/passkey reset flow is semantically equivalent to an alternative login method and if done via email is semantically equivalent to a magic link.
Which means that any service that claims to be passkey-only but supports email resets should just acknowledge that they support both magic links and passkeys as options—they're kidding themselves and their users if they pretend otherwise.
Passkeys are at least more convenient than magic links as they do not require opening an email or pulling your phone out for an SMS code. You're right though that they Passkeys + email reset is no more secure than email magic links, but I'd say email magic links are perfectly secure for most use cases. There really is no reason to continue using passwords these days and every website should switch to either magic links, Email OTP, or passkeys.
For more sensitive accounts like bank accounts and government services. You'd probably have to go through some other reset process involving real ID and possibly an in person visit to a support location.
If your passkey manager account gets frozen the clients on all your devices should still have local copies of the passkey database that you could continue to use until you have a chance to export and migrate to another passkey manager.
> hopefully Gnome/KDE implement passkey support
sigh TBH, I hope not. Maybe optionally, but for now the friction might keep companies from going passkey only, which (I think) would be a total nightmare from a security and usability perspective.
The first thing I thought when I read this is how can the author make the specific criticisms of links/otp codes and then suggest passkeys, which have pretty much the same issues x10. Like if using a OTP from your phone or copying a link from your phone when using a work PC to visit a website is a pain, how much easier/better/same is it to try and have your work computer work with your personal passkey from a laptop or something?
> how much easier/better/same is it to try and have your work computer work with your personal passkey from a laptop or something?
Passkeys support authentication via a secondary device over Bluetooth (and this is supported in every major browser on every major platform). So you can login to a site on a machine that’s completely disconnected from your personal passkey store by scanning a QR code with your personal phone.
The login flow basically goes “request login with passkey” -> “browser recognises it doesn’t have the needed passkey, and offers a QR code to scan” -> “scan QR code with phone” -> “phone and browser handshake via Bluetooth” -> “passkey handshake happens between website and phone” -> “login completes”.
I’ve personally used this flow with my work laptop and my personal iPhone many times. iOS has built in support for the Passkey QR codes, so you can scan the code with the standard camera app. Additionally iOS supports allowing 3rd party passwords managers to take over the Passkey flow once you’ve scanned the QR code. So in my case I complete the flow with 1Password.
End-to-end the flow is pretty damn seamless, I’ve never personally had it fail, and take 30seconds to complete. The most annoying part is trying to remember where my phone is.
What if the target device is a workstation or library desktop with no Bluetooth?
Then obviously you can’t use a personal passkey with it. But so what? Passkeys don’t need to address every niche scenario to be useful.
Even if we assume that you're ok with connecting discrete and disparate devices together (and you always have your personal tracking device near you all the time), Bluetooth is basically comprised of a giant bag of vulnerabilities and weaknesses.
> take 30 seconds to complete
also, ouch.
> Even if we assume that you're ok with connecting discrete and disparate devices together (and you always have your personal tracking device near you all the time)
This is a solution for the masses. If you're not comfortable with it, nobody is forcing you to use it, and it certainly doesn’t diminish the value passkeys provide over traditional passwords and OTPs for the vast majority of people.
> Bluetooth is basically comprised of a giant bag of vulnerabilities and weaknesses.
That doesn’t really matter. The whole point of passkeys is their cryptographic primitives make snooping on the handshake pointless. Everything is E2E between the passkey provider, and the site you’re authenticating against. There’s no dependency on Bluetooths security to ensure that the actual passkey handshake is secure.
> > take 30 seconds to complete
> also, ouch.
That includes the time taken to fish my phone out of my pocket.
I refuse to use any service that only supports magic links for auth. It is incredibly user-hostile, and absolutely worse from a security perspective than passwords (with a password manager). Most critically it simply does not work in my personal setup where I do not have access to my email account from the machine I am using to login, precisely for security reasons and the safety of my accounts.
Anthropic has been the once exception to this personal policy simply because Claude is the best LLM out there. But it's a mountain of pain every time I have to re-login, and I've complained to them multiple times about this.
>absolutely worse from a security perspective than passwords
Is it though? Majority (if not all) services I frequently use have email as recovery option for forgotten passwords.
It is certainly not all, and most security conscious sites offer other recovery options like one time use codes. Many also allow for time delayed account recovery, which aren’t a usable option for magic links.
In any case the correct approach here is to fix password reset/account recovery (e.g. with social key recovery) rather than reduce everything to the lowest common denominator.
It also can be said to lower security because it instills the behavior of clicking on links in incoming emails as a standard practice.
Sadly not enough people use password managers for it to be worth it for companies to target those flows.
60% of Internet users rely on a password manager, and that number is still growing by a significant amount each year.
A quick search is indicating more like 30%, which honestly is way higher than I expected. Where are you seeing 60%?
It is ~30% for personal use, and ~60% when you include personal + work. So 30% use it in both contexts, and an additional 30% just for work. A combined 60% use password managers in some capacity in their work or personal lives.
Cool, thanks. Do you have a link to these stats?
Every time I see magic links, I always think: "I thought we weren't supposed to click links in emails in the first place?".
When links in email come into mind, so does phishing.
I hate these magic links a lot.
Is anyone confused by that? Password reset links have always been sent to email.
The point is not to click suspicious links. If you know a magic link was sent, it's not suspicious.
That being said, I hate them just for the delay.
I don't like password reset links either. Send me a code I can type in, but only to the original browser session.
As someone in the security industry, I find it amazing how much we've told people (in awareness training) to "not click things on the thing-clicking machine™" while simultaneously having processes like password resets that require doing it.
™Kelly Shortridge 2021 (https://x.com/swagitda_/status/1503751776134180873)
Fake password reset links are also a common attack vector, so yes people are told to be also cautious of those.
Otherwise it's been a while I haven't seen an reset link instead of a reset code. Copy/pasting is not much of a hassle, and it works even if the mail is checked on a different device.
The only real link I had to deal with were app callbacks that were explicitly labeled as such (with instructions from the app to explain what to expect)
Be careful of those as well, but in this case it's quite simple: password reset links should only be sent when the user explicitly requests them; of you receive an unexpected email asking you to reset your password, don't click the link.
Nobody is actually confused, it's just performative whining.
Ok. So now my users get random login links for sites we may or may not use… sure, you Silicon Valley Cool Guy aren’t going to fall for it, but my blue collar Detroit UAW guys might.
Click that stupid magic link for a service we use, and they’re asked for their Office 365 credentials… all the while I’m telling them not to click links in emails.
I don't even load images. email address -> ip address.
apple's email privacy scheme seems interesting (apple always loads all images), but I don't know if there are drawbacks.
Best implementation I see of this requires you to click the link on whatever device you receive the email on, but it doesn’t transfer the session there - it just triggers completion of the login process on whatever device you initiated the process on.
This is bad (phishing). The better solution is have the login only work on the device where the link is opened, and for cross-device use to also provide an OTP code the user can read on the receiving device and easily type in on the initial device. (Or only provide the OTP code and no link.)
How is that secure against the same phishing attacks that a clickable link is vulnerable to (basically the idea that someone can socially engineer you into a situation where you think you are supposed to complete the auth flow with them, enabling them to sign in as you?)
Well, it doesn't solve the issue of someone sending you a fake login e-mail that you then mistakenly click on, that's true, but the whole point of magic links is that there isn't an auth flow; there's no password for them to steal from you.
In other words:
1. A malicious individual sends them a fake login link
2. The link can't ask them for a username and password because the site doesn't have passwords, just magic links
3. The site could ask them for your OTP code if they have one, but the bad actor doesn't have their magic link and the OTP code expires in a few seconds anyway
4. Without the bad actor actually getting access to a legitimate magic link nothing happens
It does solve the issue of:
1. You visit the site on your device at the same time as they visit on their device
2. They get two e-mails and maybe click on the one that approves your session instead
3. Your session on your device logs in; theirs doesn't so they figure it's a bug and go click the other one. Now you're both logged in.
If you require the session to be logged in by the link directly, it ensures that only the device you're viewing the e-mail on gets signed in; in the above scenario, your malicious session is never logged in, but their legitimate one is.
It doesn’t protect from telling them the OTP code, that’s true.
Agreed! If they all worked like this would be a happy camper. Nothing worse than being in one browser, opening the email, then it opens and authenticates you on the default browser or even better on a different device and needing to forward the link to the other device so you can open it there (yes odd scenario but try not to access certain emails from certain devices).
Sites that send an OTP (crazy-pink-horse-3837) that you can copy, and paste is a good middle ground if implementing the link that just Auths the original request is too difficult.
Or in the Gmail client on iOS which opens links in an embedded browser.
Even on Android that behavior is the bane of my existence.
You can change that in settings.
where? i just went through Settings > Apps > Gmail on my iphone and found nothing about this. Likewise the in-app Settings in the GMail app lets you choose which browser is the "default app" but it's already set to Safari (the other options are Chrome, by Google, and ... Google, by Google). But that uses an embedded Safari instance inside gmail, not the phone's Safari app.
To get what you want (links open in Safari.app, not the safari webview inside Gmail): configure your default browser in Settings (your iphone settings, not gmail's settings) to be Safari, and then in Gmail choose "Default browser app" instead of Safari.
It's super vague and unclear why things should work this way, and I don't know if this is forced on them by iOS or what. I'm trying to think of why choosing "Safari" in the gmail settings would use the webview instead of the app, and the most-charitable reason I can think of is that they don't want to contribute to the person having hundreds of Safari tabs open...?
Less-charitable reasons might include wanting to keep users in the gmail app for driving "engagement". I read somewhere that when apps use the in-app webview, the app dev can inject arbitrary javascript and thus has full control and can see keystrokes, what the webview's viewport is looking at, etc. I really don't think that's what google is trying to do here, though.
Wow - i even saw the words "default browser app" and did not even realize it was a setting choice. That works - thank you!
wrt reason : I think that the webview has cookie isolation from the actual app, so using the webview is a bit more privacy-protective. Google being Google that seems unlikely to be the motivating reason, but who knows what good may lurk in the heart of men...
OTP is the only sane option - there are too many edge cases for magic links to make them a good user experience
so anyone can log in as you if you receive an email and accidentally click on it?
This is a fair point to bring up.
Most sites will have a confirmation once you click the link that includes the browser version and IP address. I have seen that info only in the email itself too with no confirmation afterwords, but not for some time. Have never seen one that is just a link with nothing else that once clicked allows the other device in but supposes could be implemented that way.
The article itself is about not making them the only option (which is fair), and the OP says if they do it should login the device which originally made the request (which I agree). If the implementation is just an email with only a link, no other information with no confirmation (yes, it's fine to let this device in), then I would have to agree with you it's very risky and could allow anyone to login as you (hopefully no sites are doing this, but...)
Or if your mail client, spam filter or anything else tries to prefetch the link...
If you really want to allow for another browser to authenticate a login request, you can at least limit it to sessions coming from the same IP.
That would let you authenticate your desktop browser from an email you opened on your phone if you're on your home network, but without becoming widely exploitable by phishers.
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To be safe the link can load a page with a form / button that says confirm the login.
Some people will still click the button because they expect it will give them more information about why they received the link. You can add text along the lines of “authorize login on $other_device”, but it’s still risky.
AFAIK, McDonald’s does this with their mobile app (they weren’t letting me log in with my password) But the problem with their implementation was that the magic link that they send you is wrapped in a click tracker whose domain is blocked by pihole (and the likes), and I could not reach the actual auth URL to complete the login process.
If you have a halfway competent security team they will never ever let this fly. You are begging your users to get phished.
Almost no one has a competent security team and if they do they don’t listen to them. Security is just compliance checkboxes and lists nowadays
A fully competent security team will, on the other hand, carry out a more comprehensive threat modelling exercise and make a pragmatic choice about whether this kind of auth flow is appropriate for your usecase.
The phishing risks for a bank account login are very different than those for a ‘returning player’ login to a casual gaming site for example.
A phisher's dream.
BankID scams in Sweden worked because it did not require there to be authentication between the device that logged in and the device that authorised the login.
The victim got a phone call in which the she got manipulated into authorising something in the BankID smartphone app. But what she was actually doing was authorising the attacker to log into her online bank account.
First after several years (of blaming the thousands of victims for their millions lost) did the system start using QR codes on the screen scanned by the smartphone.
All the email scanners likely trigger the process anyway.
Solvable with the right information in the authorizing email.
Remember that the flow the magic link is part of is one you initiate, that causes you to get an email you are expecting.
That email, and the landing and confirmation page it links you to, can explain very clearly that you are only supposed to authorize this if you are trying to log in on known device in known location that is displaying recognizable number on the screen right now.
Rather than a recognizable number, users should be prompted to select a matching non-pronounceable glyph. Something like the keypads from KTANE [1].
That makes it impossible to text or speak it to a phisher.
Bonus points if you show the symbol as a noisy animated glyph, something like [2], or a link to a DRM'd video showing a symbol. That would make it very difficult to view even with screen recording or remote desktop software.
[1] https://www.bombmanual.com/web/index.html#:~:text=On%20the%2...
There is a substantial class of users this would be too much to ask of, i.e. they wouldn’t understand it or would assume that they are being scammed somehow.
The thought of using unpronounceable text to deter phishing attempts reminds me of putting illegible Unicode as challenge question answers to prevent the CSR from giving an account away to convincing social engineers.
And then when you need to provide an accessible version?
You're assuming users read.
> the flow the magic link is part of is one you initiate
There's nothing stopping anyone else from initiating the flow assuming the common implementation where only an email is required to initiate sending the link.
Yes and when you receive an email saying
Here is the link you requested from ‘Android Device’ in ‘Belarus’ - click here to sign in and allow that device to access your account - only click this if you requested this email
You don’t click the link if you didn’t request it.
You might not. Your granny? Maybe.
The phisher will be on the phone with their victim, pretending to be a support agent for the business. They will say, "Yes click the link, that's how you verify with us."
So many people on this thread leaping in with the phishing threat model.
This is a simple quick login process, you wouldn’t use it in a place where 2FA is required. It is a mistake to think of this as a substitute for 2FA just because it has some of the same elements as a secondary device authentication. It’s not intended to be a 2 FA flow though! It’s a single factor - ‘does the user have access to a device that can read emails sent to this associated email address’. We aren’t combining it with a password or anything else.
That is the same level of auth used for things on many services like ‘registering for a free account’, and frequently for ‘resetting the password on an account’.
It’s not a complete security solution and you wouldn’t use it everywhere. It would be a bad fit for a banking app or access to a publishing interface. It’s not a bad interface for things like ‘logging in to my subscription on the TV’ or ‘returning as a customer to a website I shopped with once before’.
Yeah exactly. Plus, sometimes SOMETHING will click the link before it even gets to the person's inbox (some enterprise spam filter with a sandboxed browser for example).
edit: saw that nicce basically said that a second before I hit post.
Many email clients will click the link and invalidate it - for example outlook is a classic here - so the best implementation does not use redirects/links at all.
OTP is far better than an actual magic link - you can still include a link that pre-fills the code.
Yes but clicking the link itself shouldn't log you in. Any implementation of magic links that does this is broken because of link previews.
You click the button on the page which knows the session you're logging in from and link code and does a POST which completes the login. This is how all the "login by scanning QR code" flows work.
I see - but then you can just use OTP instead - it works in the same way and you can even use it cross device
I’ve been stung by this before, where I’d already closed the original browser tab since I assumed the magic link would open a new tab (as they usually do)
> Anti-mobile. As mentioned by 404 in their own article, this breaks the ability to use in-app browsers, which is quite annoying especially for RSS reader type apps. It makes interacting with any local link in the RSS feed extremely annoying.
To be fair, in-app browsers should die, especially those without an "open in regular browser" opt-out – which RSS readers should readily offer anyway.
Seriously, this needs to be ended by the harshest penalty of law.
Throw every product manager responsible for forcing in-app browsers upon their users in jail.
What is an RSS reader?
An RSS reader is the client software for reading RSS feeds. Here's a description of RSS feeds [1]. Here is a list of some readers [2].
[1] https://en.wikipedia.org/wiki/RSS
[2] https://en.wikipedia.org/wiki/Comparison_of_feed_aggregators
Way better option: emailed OTP code and passkey with Conditional Mediation UI. If the user is logging in from a device that already has a passkey, the CM UI will let them just select it and log in instantly. If they are logging in from a device which doesn't, we can make the UX such that it asks them to enter the emailed code, and after that is successfully it immediately asks the user to set up a passkey for instant sign-in.
This gets the best of both worlds: the security of passkeys on existing devices, and the passwordless setup and account recovery for new devices.
Bonus: it even avoids vendor lock-in where cloud providers have all your passkeys.
Asking users to enter an emailed code does not protect against MITM attacks unfortunately
True, but pushing passkeys as the primary auth method reduces the risk to a great extent. It's a huge difference. As long as the user keeps using a relatively stable set of devices, they will 'approximately never' be exposed to MITM.
Also, when logging in from a new device, many accounts which use password-based auth today send a confirmation email and ask users to either enter the emailed code or click on the link. This is part of their existing security protocol. So we are not introducing a new unique thing here.
> As long as the user keeps using a relatively stable set of devices, they will 'approximately never' be exposed to MITM.
As long as the user keeps a relatively stable set of devices and knows to be suspicious if they get asked for an OTP on a device that they know has a passkey. If they don't know to be suspicious (which let's be real, most people won't), they'll happily follow the instructions and fork over the OTP to a phisher who can use it to complete the authentication somewhere on their end.
Magic links without an OTP fallback are more secure as the initial setup process because they can't be phished unless someone's actually MITM'ing their HTTPS traffic (at which point nothing can save you anyway). A phisher can get someone to send themselves a magic link, but it's much harder to get them to provide the link to them.
> Magic links without an OTP fallback are more secure as the initial setup process because they can't be phished...but it's much harder to get them to provide the link to them.
It's not that much harder. 'Due to security reasons, please copy and paste the entire link that we just sent you into the following input box. If you don't, your account will be compromised!'
That's way harder than just asking someone to do the exact thing that they've already done over and over on your legit site. Sure, some will still fall for it, but the bite rate will go way down.
Phishing attempts by definition create artificially urgent abnormal situations whose job it is to convince the intended victim that they're legitimate. A difference in degrees like this strikes me as not really something to haggle about. Users who fell prey to the attack aren't going to be reassured on hearing how much more unlikely it was.
I suspect a hidden "benefit" to the companies implementing this is that it makes it much harder to share your account. You are probably happy to share your Netflix password with your mom, but not your email password.
They can present it as a "more secure" login method, obscuring the reason they actually like it.
I'm pretty sure Medium (who was the first implementation of this that I know of) uses it as a way of blocking pay wall bypassers (which on Medium I think manipulated/deleted cookies to get around the 3 article limit).
Yeah that would not surprise me, in general. I don't think that would be 404's goal, since they provide full-text RSS feeds I could share with a friend easily, but I could see that happening with other services.
I like the Kagi qrcode login option. You scan the QR code with any device you are already logged in and boom, you can login with a button. Its like steam guard but with no app. It’s in fact so simple that I don’t understand why it’s not universal.
You still need another method for the first login.
The biggest disadvantage of this scheme is that if a malicious actor can trick you into scanning an arbitrary QR code, they can get access to your account (by visiting the login page themselves to generate a QR code, and then sending you the code).
Discord implements this feature, and this phishing scheme is extremely common: bots/scammers will message you saying "to access <some desirable content>, please scan this QR code" -- and if you scan the code, the scammers have just taken over your account. It's not much harder than rickrolling someone unless they're savvy enough to be aware of the scam.
Of course this can be mitigated somewhat by putting a big scary confirmation screen that says "don't click continue unless you're trying to log into your account from another device", but 1) users don't read, they just click "continue"; and 2) the attacker controls the narrative before the user clicks the QR code; they can craft the language to make the scary warning screen make sense to the user ("yes, I am trying to log into this discord server that this person sent me an QR code to").
I feel like there should be a way to implement this in a phishing-resistant way. Maybe instead of a QR code some sort of video stream that updates dynamically? That would at least be much more difficult for attackers to pass through to the victim.
Magic link are so, so stupid. Sure, make it an option for Grandma, but don't trot them out like they're amazing, they're terrible. God I hate the way the Internet is going - idiots making technical decisions.
They are sometimes required. Say you are on a mailing list for some company you gave your email to at some checkout counter one time, and you want to unsubscribe. You probably don't have an actual account with a login with that retailer, they just have your email address.
In this case, what alternative is there than having a magic link in the footer of that email that says "unsubscribe" that includes a token unique to that email address that acts as proof of owning an email account when you then click that link and ask to unsubscribe?
There are many options where such links are a reasonable option. I'm okay to receive such a link to validate my e-mail for an account creation, or to unsubscribe from a mailing list at a place I don't have an account at, or to display an order status page at a shop where I ordered as a guest without creating an accoung.
But using them as the only option to login is really, really annoying. Mails can get trapped in spam filters, delayed by intermediate server overload or spam filters that sometimes take 10 minutes, servers doing graylisting... Plus all the other annoyances listed in the article (e.g. multi-device users, in-app browsers). At the very least, support passkeys if you really don't want to store (hashed) passwords. And no, SMS is not an alternative: I was several times barred from logging in to a service because SMS wasn't properly working (can happen easily while roaming abroad).
Yes, sorry. I mean in the same way as the other person who's replied to you. Don't give me an "account" somewhere I'm expected to use on a regular basis but require me to use magic links.
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Adding to the article:
I seriously HATE magic links. My email inbox is barely better a social network's time suck. Lots of urgent, little important, wrecks any flow I had.
Forcing me into my inbox is highly likely to cause me to forget about the reason I was there (to get into your app). Or, at best, it slows me way down and nearly always breaks my flow.
Perhaps this is acceptable for the security boost (?) for the average user, but man, when I get forced into magic links I sometimes just abandon the app altogether.
Disclaimer: 1. I have/pay for a password manager, which helps with the forgotten password problem a lot. It also allows me to have extremely hard-to-crack passwords.
Totally agreed - a correctly used password manager is many, many times easier and faster to use than so-called magic links. It's not even a contest.
I'd even say magic link emails border on misuse of email; they're a fundamentally different form of communication from all other uses of email. It's not easy on neurodivergent brains to deal with that combination of pollution (magic links in my inbox) and distraction (actual emails in my face when I'm trying to log in and was not trying to check my email). Protonmail's client could really make my day if they found a way to reliably separate those 2 channels so I didn't have to even open my inbox to get login codes/links.
What I don't understand is why I've never been prompted to use a password manager by any site with a signup flow. It seems easier to normalize their use through messaging than keep acting like passwords are supposed to be something you consciously remember. Nobody should remember their passwords, except for maybe 2-3. But now we're moving toward a world where login just means more friction and less control instead...
Trying to explain to users of an unrelated site how to use a password manager sounds like a support nightmare.
That is a very good point! You'd have to be careful to craft the messaging so that it doesn't imply you can help troubleshoot the password manager.
But something simple could work. Already you usually have a note under a password field, "Must contain at least 8 characters and at least one special character" or something to that effect. It could also have some note about "We suggest a randomly generated password from your password manager."
I'm not building this out so I don't need every hole poked in the idea, just seems like it could work.
If someone is going to do this, 'At least one special character' etc. is not the way to do it. According to OWASP guidelines, a secure password must enforce a minimum length but not any other specific criteria, because they actually end up reducing password strength. Instead, the best option is to add a password strength indicator below the password entry field, to encourage the user to create a strong password. The help text can also mention using a password manager but it's difficult to do in a good way.
One of my pet peeves is when rules counteract the purpose they are supposed to serve, usually because of incompetence. Two years ago, I worked for a few months for a company where time reporting was accessed through a specific web page.
They required the password to be changed monthly, have at least 10 characters, at least one number and at least one special character. On top of that – they locked out password managers and pasting. "We need to make sure you are the one logging in and not a hacker that hacked your password manager" they explained when I asked.
Out of spite I went for "Password12!" the first month and "Password123!" the month after, at which point I received an email from the IT department explaining to me that my choice of password was endangering the corporations security.
> I received an email from the IT department explaining to me that my choice of password was endangering the corporations security.
Sounds like they were logging/storing passwords in plaintext.
Or offline cracking passwords using a wordlist.
Isn't it nice that hackers give up as soon as they realize they can't paste the password in?
And password managers (keepassxc anyways) have a pretty nifty auto-type feature that gets around that anyways.
Have you heard of the Cobra Effect?
You can tell them to write their password on a piece of paper in their drawer. Seriously.
Many home users are pretty good about protecting important scraps of paper. The government gives us plenty to hold onto. Even if they’re a grandma that doesn’t understand all this password manager mumbo jumbo, they can deal with a notebook and be better off than using the same password on every site.
Magic links breaking my flow is my top issue as well. My inbox is distracting: don't send me there. One affordance I've seen was a site that detected I was using gmail and crafted a link like https://mail.google.com/mail/u/0/#search/example.com, which brought me directly to the email I needed, while hiding everything else. I think it did a MX lookup to guess my provider.
I wish magic links would go away, but if they need to stay, that approach was the least terrible.
Good point! I've seen this search link setup before and it was... somewhat palatable. Still more bad than good but at least better UX.
I use magic links for my enterprise application. In my humble opinion I believe magic links are fine.
Almost everyone outside of some HN users use email regularly. They have it open on a second monitor and it is an important part of their workflow.
If their companies are not super tech savvy and not using SSO, the users probably at least have a company email address they’re logged into.
I don’t think it’s worth over optimizing for a small percentage of users. Worst case scenario you need to contact support.
99% of enterprise users will be fine with magic links, compared to dealing with people who use horribly weak passwords. Most of them seem to prefer them to passwords.
SSO is always best option if available but magic links are definitely second.
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Calling these links 'magic' is an insult to magicians who spent years mastering actual sorcery. We're just passing around URL-encoded tokens.
Good post. I chose to only implement magic links in a previous project and had an issue with users complaining that the (one-time) link would always be expired when they clicked. I could not reproduce it and just left it. Then this thread appeared and I instantly knew the problem: email client previews. Lesson learnt.
The article doesn't even touch "people enter their email incorrectly when registering an account".
I've received magic links to my Gmail account that belong to other people, for accounts that have ordered flight tickets, or clothing, or digital services.
Those people, I guess they now have no way to access their online account, as they cannot password reset (if that was the fallback), or change their email (usually requiring confirmation), or receive their magic link.
There's nothing I can do here, except to delete the email, I don't have any indication as to what the correct email should be, and the person's name is the same as my legal name and there are a lot of people with that name in the World.
Few services verify an email during sign-up, because I'm sure data shows that added friction during sign-up results in fewer people signing up.
You're right, I forgot to even cover that part because I was focused on how annoying they are to me as a user, not necessarily as a service provider. I also forgot to mention how they train people to click on links, how my inbox now consists of dozens of emails per day telling me to either click to login, or warning me that I logged in.
I have my own domains for email so I haven't had the issue of someone else entering my email but I keep hearing from friends getting that.
This happens on my Gmail all the time.
Frankly, if somebody else uses my address for a service and I'm receiving anything other than email verification from that service, I'm reporting it as spam on both Gmail and Fastmail because that's what it is.
Virtually all online streaming services in India now use a OTP sent to registered mobile number as the way to login to the app on any device.
Magic links and OTPs have become common for many other sites I use -- Udemy, Teachable etc. come to mind.
Recently I bought a cheap "smart watch" for my kid. Mostly for the digital display with configurable clock faces and simple step counting. The app would refuse to activate the watch unless we provide a valid mobile number and OTP. Why the hell do I need to give them a working mobile number just to use a smartwatch. Even if I wanted (which I did not) to get notifications / calls / texts / caller ID / contacts from my paired smartphone ... the smartwatch app does not need to know my phone number for that functionality to work. Feel so powerless.
My data point as an edge case: on a certain website, I have a throwaway account registered with a throwaway gmail account. I don't use that gmail account for anything else, and in order not to affect my regular Gmail login, I use incognito window. Now, whenever I need to log in to the website on a new device, I have to also login gmail as well (since the login credentials are never kept between sessions). This has been very annoying, and would not happen with password with 2FA.
The 404 article irked me a lot, thanks for writing this.
You're welcome. Been thinking about it for a few days, and I had to do it. I don't disagree there's some benefits but being told "IT'S BETTER!" annoyed me quite a bit.
I'm having a good experience with a recently implemented magic link system. I did it via WhatsApp instead of email, which is much more reliable. Of course, this is only possible because in my country every single person uses WhatsApp.
I'm building something for a very tech illiterate audience, and everybody loves the simplicity of it.
I've wondered about doing this. Does WhatsApp let you send messages to arbitrary users via an API?
That looks even better than I hoped. Is this free?
I have a very personal reason to hate magic links:
I'm quite fast at passwords and 2fa. The whole thing is second nature, I have a password scheme to deduce the password for any site but keep them long and high entropy, and I can do 2fa calculations from any trusted device without taking my hands off the keyboard (thanks to oathtool), and anyway my passwords are sync'd securely and I can look them up with hands on keyboard.
This is strictly better than "single point of email failure". Why force me to be less secure and less usable.
Please, just allow me to use passwords and regular old TOTP.
Honestly, having run a number of experiments with magic link, I wouldn’t recommend them. We saw our login success drop noticeably. We tried a few different approaches over the course of a quarter but even our best attempt only mitigated the drop compared to having email/password and Google Login.
Obviously, your mileage may vary but it was a good reminder to always validate your assumptions, especially in your critical user flows.
I'm super interested as we've been debating adding email/password (since we only use Magic Links at the moment).
How are you tracking login success rates?
Pretty straightforward: you send an event for which variation your user saw and another when they login, attaching the login method to the attributes.
You can use Mixpanel or Heap, which have mechanisms for mapping the non-logged-in user to your verified user on login, though you might need a bit of custom code to do it.
Ah. We use June.so ; I'm assuming they might have a similar mechanism. We'll try and log login attempts so we can track this. Thank you!
No worries! Our experience is that the hardest part (and it's not trivial) is associating the "anonymous user ID" to the newly logged-in user. Segment has an identify() function (I think Mixpanel has something similar), where you link the aliases, which then makes the reporting work.
I've not tried June, so I can't say for sure, but it's a pretty common feature for product analytics. I'll be surprised if it's not possible.
I was surprised to learn how many people never save passwords and just reset it via email whenever they need to log in.
I've never liked magic links. I've found multiple sites that will just clobber the existing login session when you access the magic link, meaning someone could trick you into logging into another account.
I like magic links (as long as they self-renew the cookie so I never have to log in again) but you do highlight the critical need for a good landing page if you use them, like "are you sure you want to log in as SomeUserNameGuy? You're currently logged in as SomeOtherUserNameGuy."
I do have a good use case for magic links.
I creates a bar management/sales platform for our group of friends. It's self service so people purchase their products on their phone and pay later.
People get... intoxicated... after which passwords appear to become quite the problem. Magic links solved that.
To solve the multi device and in-app browser problem people can also open the links on another device. That'll show a short code they can enter on the original device to actually log in. It's not perfect, but it works.
I do fully agree that passwords should always be an option as well.
What a good idea to get people used to clicking on a link in an email to login. Magic opportunities.
Been saying this for a bit now. OTP/magic links have some upsides but the second your SMS or email provider doesn't deliver said thing your users are in trouble.
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Most internet users (who aren't tech savvy and will never be) will find magic link || mailed OTP way easier than passkeys accross devices, etc..
Oh I hate how Slack uses this. Because if extensive use of magic links I lost track about my two accounts and several spaces.
> Stratechery, powered by Passport, uses this type of scheme (click link OR type in OTP), which is still shifting annoyances onto end-users to free developers from implementing passkeys, but at least has a bit more of an appreciation for end-users.
With Stratechery, once you get to the website with the magic link, I can then copy the authenticated podcast RSS feed to Overcast and the authenticated RSS feed for the articles to NetNewsWire.
Those subscriptions are then synced to Overcast and NNW on my iPad and Mac via iCloud.
Each podcast RSS link is personalized and you go to the show notes page and click on the link to Manage your account. It will take you to the website using the embedded browser where you can manage your subscription and get access to the various feeds.
Speaking of Overcast, even though its doesn’t create a username and password by default, you can create one. But it’s only to access the web version of Overcast.
Yeah the Stratechery implementation for podcasts is great. The more annoying thing is each of them has its own domain and requires logging in, if you don't know you can dig into Stratechery.com. I would prefer if I could login to it with a passkey or username+pwd, but it's a much better system overall than just dropping an email link.
Once you subscribe to one of the podcasts, you can choose the “Manage your account” link from the podcast notes and choose the “Delivery Tab”.
It will give you all of the links to all of your podcasts. I did this from the “Dithering” podcast notes
I hate those tragic links, some of them were sent from third party and infested with tracking links. Worse, it looks like from the site I'm logging in to, but the href is a tracker with redirection to the actual link. I see this frequently because my dns blocks those trackers.
I *hate* magic links. Just let me use a damn password.
I once had an app send me a code in the email. But if I opened my email app to check the code, and then return to the app to enter it, it would lose context! It would ask me to enter my email again, and proceeded to send a new code. There was no way to log in using only my phone.
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I'm okay with magic links IF the website using it doesn't invalidate my session for no reason after some random period. If I have to do the email song and dance every week I'm very likely to eventually not bother with the product (looking at you Claude).
I don't like magic links but OTP code via email or sms has preferable set of trade-offs.
While I agree with most he says, I really don't get why people would push for passkeys like this, it's probably the worse system in existence in terms of UX (as the more likely to get you locked-out of your account) while providing minimal security benefits (the account recovery mechanism is the weakest link in the chain, and as such it's not any better than magic links). The only ones benefiting from passkeys are Google and Apple (and app/website owners who can't avoid mismanaging user passwords, but they have little stake in this game anyway).
Or the involuntary option. Here is an example from Lowes
1. enter username
2. choose password or magic link (select password)
3. enter password properly
4. Thank you for logging in. Please click your magic link to log in.
Why did you waste my time putting in a password when the magic link was the only option?
404Media article about Magic Links: https://www.404media.co/we-dont-want-your-password-3/
Our response to above: https://wideangle.co/blog/passwordless-authentication-magic-...
Conclusions:
Magic Links good? Yes.
Magic Links the best? No.
I agree with magic links being bad, but passkeys aren't the right solution for multiple devices either, because it requires sharing the account or password manager they're saved in between devices, and I'd rather keep my private accounts and passwords away from work devices. With plain old passwords, I can open my password manager on a trusted device and type the password into an untrusted one.
Expensify.
We dumped them for a host of reasons, but included in there was their use of tragic link logins.
Absolute clowns. Glad to see this practice getting the negative attention it deserves.
I usually implement the whole username/password auth flow, but recently used only magic links for a simple application.
Since the application only sends a weekly email (a markdown template for goal/task tracking) it seemed easier to just use a magic link, only.
I am happy at how much easier the auth code ended up, and fail to see much downside for such an application.
I'm not sure it would be a good system for more complex apps and services.
I have a system where users log in extremely infrequently. Tempting to move away from username & password because they just reset every time anyway.
Yeah - that's my thought too, the service I use them for is not something people often log into. Sometimes never.
Revolut [1] does this and while I like their service overall, I hate the login mails. My email box is full of these login mails and it feels like abuse of the email system to me. I have all kinds of alternatives, Yubikey, TOTP, Password Manager etc. - everything would be better than this magic login link.
So in case of temporary email delivery problem no banking?
I had this case recently: Sending a job application, so wanting to check what my LinkedIn actually says (I don't use or even update LinkedIn regularly). Now LinkedIn thinks my login looks suspicious and sends a confirmation email. (It does that nearly every time the rare cases I log in, probably because I delete cookies.) But the mail doesn't arrive. My email provider is usually very reliable, but later I learned that just in this moment they experienced multi-hour delays. While this was not a magic link it shows that any login requiring a quick email delivery can fail in the worst moment.
> Of course, as stated in the article, such email links are harder to phish than passwords
On the other hand, training users to expect and use hard-to-read login-links in emails is not really good either. It promotes a broad range of scams, phishing, and potential malicious code exploits, even if the a particular sender's site has been hardened somehow. (e.g. a TOTP app on a phone.)
It’s hard to do right. I made mailslurp for this reason to allow end to end testing of magic link flows using disposable email accounts.
Thank you for writing this! Getting users to implicitly trust clicking a link as a login mechanism....what could possibly go wrong?
From a developer perspective, I like magic links. They help verify an e-mail address, and log you in at the same time.
Like there's no other way to verify an email address. From a developer perspective, I hate it, because it's yet another functionality that I need to add and support in my app.
Why doesn't sending an OTC to an email and marking it verified if they put in the code also work?
Feel like the solution to this problem is probably to offer an app that turns magic links into notifications. As well as to probably untether the magic link from the cookie in the browser, so that you are not required to hit the magic link in the same browser that you called the link from.
claude.ai supports only either magic email links or google sign in. definitely a factor in why I prefer ChatGPT.
I just signed up for Claude yesterday and I didn't even realize that I didn't enter a password. It was when I wanted to use it on my phone (with Firefox, not the app) that I realized that there was no Claude entry in my password manager. It made me irrationally angry for about 5 minutes, and had I known it in advance, I would probably not have bothered.
Also encountered this today and I didnt remember what email I used to login, so I tried both but now I seem to have 2 claude accounts, ugh…
I also find their magic link annoying, but since claude.com doesn't log me out all of the god damn time like chatgpt.com does, Claude is winning this round too...even though this is not a factor in why I prefer one vs the other.
Related thread from September 2024:
Some users use email flows, such as "magic links", instead of bothering with passwords at all.The "email is authentication" pattern https://news.ycombinator.com/item?id=41475218Fun domain name.
Unfortunately blocked on my (work) network -- classified as miscellaneous / unknown category.
I have to admit I bought it mostly to annoy a few very specific friends, but then I kept using it. I would not recommend trying to host anything serious on such a TLD.
If you check the early comments on the thread I posted the full content for someone else who could not reach .zip domains.
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Magic links are one of the worst things ever introduced on the internet. They're slow, painful, and just such a dumb idea.
As someone that does this for a living, 100%. Email OTP is a great alternative that splits the difference of magic links vs passwords.
Agreed with some other folks that Passkeys is not a replacement for email verification.
Sorry to ask - I don't have personal experience using such a system.
Would it be possible to bookmark the login link so that in the future I don't first have to go to my email in order to log into the service?
No. The links are temporary.
And worse (sometimes) consumed by email scanners. There's all sorts of hassles with them. Email deliverability often an issue too.
Oh, I see. Thanks! So, they're basically the second part of 2FA?
They aren't really 2FA at all since often you don't need a password. To login you just type your email and enter the code you got from the email or click a link.
Shopify works this way where buyers don't have passwords and only log in with codes sent via SMS/Email.
You stay logged in due to cookies. You don't need to keep the login link.
Except that some people prefer to purge cookies when closing their browsers. And the session typically doesn't last forever, even if you keep the cookies.
Username and password combo works. All these ceremonies around OAuth, passkeys, and magic links solved one problem but introduced two more. My job as a service provider isn’t to coddle people who can’t be bothered to use a password manager.
Auth is the worst part of building a service and sucks all the fun out of it. API auth is a mess because people can’t keep a token string secret. Now we need JWTs, OAuth, token refreshing, and a whole bunch of BS that no one enjoys.
One reason why OpenAI and Anthropic APIs are so much more fun to use than Google and AWS offerings is that you get a token and are responsible for keeping it safe. It makes the entire workflow dead simple. I’m not creating a new project or fiddling with IAM just to try out an endpoint.
Your job as a service provider is, in fact, to minimize the likelihood that you will manage to communicate the passwords of your users to outsiders, because those passwords are very likely to be shared. That passwords should not be shared doesn't reduce your responsibility.
Magic links are a easy way to move the responsibility of security off to the user and remove the risk of managing access controls.
Most users do live with a single device. If they have a work computer, they also have a work email (the client of which is unfortunately probably already opened for other reason when they want to login to the site).
The most-devices people I know are those who have a laptop, phone and tablet. That's it, I literally cannot think of anyone I know with more then this, and most of those with tablets are using it for games or reading or for the kids.
Magic links are indeed the best solution for the average user. Type in your email with autocomplete, get a notification from the mailbox, click, click, and you're in.
“Type in your email with autocomplete, get a notification from the mailbox, click, click, and you're in.”
My autocomplete can fill a password or passkey in too. Don’t waste my time.
I really hate magic links. Only time I think they could be acceptable is if it is an app where you just log in once or maybe once every couple of years.
Nostr Login using NIP07 is amazing.
There's even cooler ways that are already working including nsec bunkers.
This is the way of the future IMHO, most people just don't know it yet.
I hate magic links. Being forced to switch applications to wait and hope an email will eventually arrive is a fundamentally bad experience.
I recently encountered a food delivery website that insisted on a magic link / 2FA code check after a password login. Come on... I'm trying to order a pizza.
If you want strong security, offer passkey login. It's safer than email and much more user friendly especially with FaceID/TouchID on Apple devices.
get Mail on different device, copy link and send it to myself via some messenger, link preview uses up the login %)
Usability issue aside. ... Using SMTP as the only login factor sounds very insecure to me.
Magic links are so useful in specific circumstances. We have a client with hundreds of users that infrequently need access to a bespoke tool. Setting up and managing user accounts for them is out of the question, but a magic link letting them sign in using an email of their corporate domain solves the issue easily.
I completely agree. I find magic links much more of a hassle than a password.
From a .zip domain. Irony.
Thanks for recognizing it, it was absolutely by design!
No issues for me.
Just use email and password, companies. Please. I have a password manager, I will stop using your service if it's a pain to login.
Even something small thing like email -> hit enter -> then we show password input, will cause me to stop using your service.
Yeah, and everyone who did not flunk security training knows not to click on the links.
Don't send me a link, tell me where to find it, after I log in.
> I don’t have my email on my gaming PC, nor do I have it on my work laptops.
What? You have your email on literally every device -- be honest.
Nope, I don't have email on my phone. This breaks magic links all the time for me. In many situations I wouldn't even be able to configure my phone to show me my email, because I don't know the password, it's in my password manager and is lke 52 random characters.
I think it's interesting that the author has chosen to not have email on PCs, but I can see why. I also completely get why they'd opt to not have private email on a work laptop.
I don't have my home email on work devices. I also don't have my email on my gaming PC (I agree this must be rarer). I don't have all of my work emails on my personal devices either. So now when I log in I need to DM myself links over Slack, or forward emails around...
Just because you make exceptions doesn't mean everyone else does
Just a pet peeve with passkeys (and other authN) that presses users towards biometrics -
In the US, because the Fifth Amendment Self-Incrimination Clause, passwords cannot be demanded. Passwords are testimonial evidence. [United States v. Hubbell (2000); re Grand Jury Subpoena Duces Tecum (11th Cir. 2012)]
Biometrics on the other hand are not. The court ruled that a defendant could be compelled to unlock a phone with biometrics because it is not testimonial. [Commonwealth v. Baust (Virginia, 2014); State v. Diamond (Minnesota, 2017)]
Basically, passwords cannot be compelled to be disclosed, while biometrics can.
There is similar legal stance in Canada, UK, Australia, India, Germany, and Brazil to name a few.
Finally, under duress, passwords can be held, while biometrics cannot, without self harm.
> There is similar legal stance in Canada, UK, Australia, India, Germany, and Brazil to name a few.
There is not a similar stance in the UK. You can be compelled to provide a password. Section 49 of the Regulation of Investigatory Powers Act 200 (RIPA and let that doublespeak sink in a second) allows the police to compel it subject to a warrant from a judge.
The sentence (subject to sentencing guidelines) is up to two years in prison or 5 years for national security / child indecency cases.
You can claim you don't remember/know it as a defence, but in most cases that's not going to be believed by a jury.
In theory once you got out you could be re-served with the notice and face another 2-5 years. Rinse and repeat.
>but in most cases that's not going to be believed by a jury.
Is there are least some argument of reasonability? I have an old Runescape account I would love to be able to get back into, but I don't even remember the email it was tied to, much less the password. I was a kid back then so even the card that paid for membership was my parents. Is there some expectation that the prosecutor has to show the account was accessed in the last X years, or is this effectively a backdoor to keep someone in prison indefinitely?
Sure, it's called trial by jury.
A jury is gonna believe you forgot the password for an account you haven't accessed in X years. They're not gonna believe, without a lot of evidence, that you forgot the code to the smartphone you use every day.
And that's assuming that the judge even considers it reasonable.
There's no doublespeak there. To regulate just means to make regular. If they make the reprehensible the regular way of doing things then they've still done the job they're nominally supposed to do. They could say all investigations have broad sweeping powers going forward and they would still be regulating investigatory powers.
We want regulation to be for the benefit of all so we attach an emotional meaning to it but nothing about the word says it has to be beneficial.
What happens in the case of plausibly-deniable keys? Say someone has an encrypted drive with a hidden volume, one key decrypts decoy files and one decrypts the true files. If the person gives up the key to the decoy files, is the onus on the prosecution to prove additional keys exist or on the defence to prove they don't?
Not a lawyer but I expect it would be on prosecution to convince a jury that they had failed to make "a disclosure of any key to the protected information that is in his possession"
as per RIPA 2000 Section 50, 2 a)
To do this, they'd likely need some evidence to persuade the jury, beyond reasonable doubt, that the encryption system had such a feature.
> In theory once you got out you could be re-served with the notice and face another 2-5 years. Rinse and repeat.
Is there no concept of double-jeopardy in UK jurisprudence?
Not from the UK and not a lawyer, but if a new warrant was served, then not providing the password would be a new offense and double jeopardy would not apply
The UK always surprises with how close their reality is to V for Vendetta.
You can’t unlock your iPhone with biometrics at first boot, and holding down the two side buttons will make it so your phone immediately disables biometric unlock, and instead requires your passcode for the next unlock.
But none of this has much to do with the biometric auth you do with passkeys, because passkeys are used in places passwords would be used — logging into apps and websites. Which you see only doing when your device is already unlocked and you are actively using it.
> holding down the two side buttons will make it so your phone immediately disables biometric unlock
Also pressing the lock button five times in a row.
You can also quickly press the lock button 5 times and then your iPhone won't unlock with Face ID until a passcode is entered.
Biometrics then need a mix of non-testimonal and testimonial input. ie it only unlocks when it sees it is your face and your face blowing a rasberry. Can you be compelled to blow a raspberry?
In the US, the answer would be yes you can be compelled to blow a raspberry.
What I'd recommend is if you're worried about this (or worried about it in certain instances), disable biometrics to unlock the device itself. Then, passkeys on it don't really matter anymore.
On iPhone, you can quickly do this by holding down the lock button and either volume button until the shutdown screen appears. Once it appears, your phone is now locked and it will only accept the PIN (you don't need to actually shut down).
Alternatively one can press the lock button 5 times quickly.
On Android, pressing lock 5 times quickly automatically dials 911.
Thankfully, it doesn't. It asks you to confirm by sliding some on-screen control, and then dials 911 / 112.
If it dialed immediately, I'd be in jail already, going by the amount of times I managed to trigger the "call 911?" screen by accident in the last year or so.
This works if the event, which forces unlock, is expected. Often such events are not expected and there are but seconds.
I beg to differ to those who write that such events are expected, just press a few buttons, disable, or something similar.
Imagine you are not in a a relatively "democratic" nation.
(0) You are asleep. You phone is on the nightstand. At 4:00 in the morning, you wake up with a rifle stuck in your face.
(1) You are walking down the street, middle of the day. Your phone is in you jacket inside pocket. Two burly individuals grab each of your hands, tie them and then toss you into a van that just pulled up.
(2) You are walking around, let wind on your face and feel it in your hair. Your cell phone is in your jilbab or burqa, you changed out of. A rock hits your head and you black out.
(3) you walk into the public WC/bathroom in the bar, but you do not take your phone in with you because it is just ... ick. You come back out and the phone is in the hands of a local law enforcement agent.
Each one of these have happened in real life. There are just a myriad of real scenarios where someone is not in reach of their cell phones.
You have already described prerequisites. It is unwise to use biometrics if you are a person of interest in a "not so democratic country". And to get a riffle to your face they should demolish a door which is commonly steel in a "not so democratic country". This is loud and gives plenty of time.
Nothing happens out of the blue. People don't get searched randomly except some rare places where an iPhone is the source of danger itself being a valuable possession.
If someone feels that such events could happen it is mandatory to do OPSEC. If not, bad for this someone. Anyway, a proper torture will reveal the password in a "not so democratic country". Which also happens in the real life.
On my android phone, if I hold the power button I get the option to "lockdown", which immediately locks the phone and disables biometrics for the next unlock, requiring the PIN/password.
I assume that would work for the situations you have in mind.
The event itself is often expected. Nothing happens out of the blue. The exact time of the event is unknown. So, extra precautions like disabling biometrics before leaving home is a normal risk mitigation practice.
On my android phone, if I hold the power button I get the option to "lockdown", which immediately locks the phone and disables biometrics for the next unlock, requiring the PIN/password.
I assume that would work for the situations you have in mind.
Yup and iPhone has the same feature. Seems like parent may not be aware of this.
> There is similar legal stance in Canada, UK, Australia, India, Germany, and Brazil to name a few.
In the UK the Regulation of Investigatory Powers Act (RIPA) makes it a criminal offence to not divulge a password if compelled via a RIPA notice.
I wonder what would happened if you willingly keep providing a wrong password. The possibility of your device malfunctioning IS and always will be > 0.
Can the judge really throw you, and re-throw you multiple times to jail because the password you keep providing did not work?
I agree, and I wish there was an option to always require both a passcode/password AND biometrics in iOS and MacOS. While it would become a hassle having to do it every time, it would at least guarantee that one could retain their 5th Amendment rights if the device were seized.
Having no backup to biometrics could lock you out permanently if it stops recognising you for some reason, so it would need to accept just the password, and at that point you can just turn biometrics off entirely
I've always thought of passkeys as a good 2nd factor in conjunction with a password. Similar to the way you'd use a Yubikey or anything else with FIDO2/WebAuthn.
Seeing passkeys as a dedicated login on their own is...strange. For all of the reasons that you indicate.
Would you happen to know what the rule is on Yubikeys and the like? I assume if it's PIN-protected, it counts as a password but what if it's just set up for tap-to-unlock?
Not a lawyer and do not know your jurisdiction.
I extrapolated this as anything that is in the mind (PIN, password, some secret) cannot be demanded, while anything outside of the mind, biometrics, geolocation, physical object (key) can.
Again, I am just a hairless monkey smashing rocks together. Consult experts.
In the US this is a pretty good nationwide summary.
Of course they can use that. The Fifth Amendment protects the right to not testify against yourself. You can keep silent. That's it about self-incrimination. The government can seize any physical object and do essentially anything it wants with it with a warrant. They can physically decap a TPM and read the security key if they really want to.
Thank you for the correction on the UK laws.
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Let me tell you about the time Epic's magic links were delayed six hours. I couldn't login to fortnite. It was absolutely tragic. /s
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Firewall blocks that link
Probably the entire .zip TLD.
Yeah. To be honest, I kind of setup this blog as a joke when the dot zip gTLD came up, as an inside joke with a few fellow security people who (rightfully) are against the ever expanding list of TLDs we have to deal with.
What's wrong with ever expanding list of TLDs? Is there a security threat or you just don't like it or?
Some of them make it way easier for threat actors to obtain large amounts of domains for cheap or free, without fear they'll disappear right away.
Paul Vixie had a great talk and research about this ~2018: https://www.youtube.com/watch?v=nkoNjntc5Lw
Because of the risk of auto-linkification, I'm of the opinion that browsers should put the entire dot-zip domain into the this-is-dangerous realm with big scary warnings if anyone follows a link. (Or at least any file downloads.)
Because I'm an idiot who likes hosting stuff on bad gTLDs, here's the markdown content of the actual post for you and everyone behind some corporate firewall that blocks dot zip:
The term "Magic Links" once meant a [futuristic PDA](https://en.wikipedia.org/wiki/Magic_Link). Nowdays, companies like [Auth0](https://auth0.com/docs/authenticate/passwordless/authenticat...) use it to refer to the slightly-magical feat of including a login link in an email.
Last week, the great website you should subscribe to if you haven't already (it's great, when you're not logged out), [404 Media](https://www.404media.co/), posted ["We Don't Want Your Password"](https://www.404media.co/we-dont-want-your-password-3/) in defense of so-called magic links.
Of course, as stated in the article, such email links are harder to phish than passwords, can't lead to a breach of passwords, and protect the site itself against users who might reuse passwords previously compromised.
The article even covers some of my annoyances with this system, but throws out this sentence:
> [We find this to be a much easier login process and wish it was more common across the web where appropriate.](https://www.404media.co/we-dont-want-your-password-3/)
Easier than what? Easier than a long password, without a password manager? Easier than a passkey? Easier than an OTP sent to the same email address?
This sentence reads to me as one written by someone mostly working and _living_ from a single laptop and mobile device. The second part of the sentence, calling for more sites to do this is why I am writing this.
For any scenario with a minimal amount of complexity, like users with multiple computers, and you're looking at a scenario where the site's unwillingness to deal with other login methods shoves friction on the end-user.
### What makes them tragic:
1. Multiple devices. Who doesn't use at least a few computers weekly? I don't have my email on my gaming PC, nor do I have it on my work laptops. 1. Slower. From 2 seconds slower to minutes slower, depending on SMTP delays as well as how awkward it is to get the link to the right browser. 1. Anti-mobile. As mentioned by 404 in their own article, this breaks the ability to use in-app browsers, which is quite annoying especially for RSS reader type apps. It makes interacting with any local link in the RSS feed extremely annoying. 1. Indirect security downsides. Pushing people to access personal email on work devices (or vice-versa) isn't exactly a win for security.
Another annoying _passwordless_ system is to email or SMS an OTP the end user can type in.
While this sucks, it at least allows you to easily log in in situations where you don't have a clear and easy copy/paste path from the email client to the browser you want to log in to.
[Stratechery](https://stratechery.com/), powered by [Passport](https://passport.online), uses this type of scheme (click link OR type in OTP), which is still shifting annoyances onto end-users to free developers from implementing passkeys, but at least has a bit more of an appreciation for end-users.
If you insist on using magic/tragic links by default, at least consider offering a robust alternative, such as [passkeys](https://fidoalliance.org/passkeys/), especially if your audience is technical and privacy-focused.
URL encoding solves part of this.
If it fails, prompt for OTP on the fallback /Verify/ or /code/ page.>Example.com/Verify/5W9GFLocal convenience cookie for authenticating device and permi-cookie for requesting device.
Permanent cookies should be accompanied with a 4 digit numeric PIN between any critical functions unless the session is new.
You are a national treasure.
> What makes them tragic:
> 1. Multiple devices. Who doesn’t use at least a few computers weekly? I don’t have my email on my gaming PC, nor do I have it on my work laptops.
"Who doesn’t use at least a few computers weekly?"
I don't. And many, many other people.
See what I did there? I assumed that everyone's like me, just like you did in your blog post. Without data, both of us are wrong.
----
I'd add that magic links also act as a distraction: you open your email client, and it by default opens your inbox, and you start going through all of those unread emails that you just found in your inbox...
Shopify is a big proponent for magic links because they went all-in on their new "Shop" customer accounts. What a disaster. Branding something with such a generic word as "shop" is terrible and average customer doesn't understand that it's supposed to be a brand name.
Shop is the same as Shopify? Thank you (seriously) for pointing this out. I've been getting Shop emails and I had no idea.
Haha. Thanks for proving my point!
> "Who doesn’t use at least a few computers weekly?" > I don't. And many, many other people.
When you consider that a smartphone is "another" computer (or for many users, the computer that is not the smartphone is the "other" computer), I imagine that number goes way up. Someone using a computer at work and a personal phone, for example.
I've not seen Shop but always liked the simple ShopPay UX.
I got one of these a couple days ago. I thought it was a well timed scam at first.