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Ask HN: Why aren't one-time sign in links more popular for authentication?

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Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#111
post #31

Oh, this is so terrible. I hate this approach with a passion. E-mail is NOT INSTANTANEOUS. It was never meant to be. It happens to arrive quickly for most people most of the time, but you should never, ever, base a service on that. Many systems have greylisting in place: a new sender gets a 4xx reply, and is allowed through only on subsequent retries after a pre-set time period. This is often as much as 30-60 minutes…

Right, it isn't authentication, it is only account control. If you have to login to your email anyway. We just need simpler 2FA options. FIDO is moving the ball forward in the right direction but they don't seem willing to push the final steps.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#112
post #78

Earlier quoted context omitted.

Every system that relies on passwords also provides a password reset facility. The facility typically sends a token to your email address and allows you to set your password that way. Doesn't this mean that a system which relies on an token sent to you is no worse that a system with a password? With a password, you can guess that GTP used the same password on Hacker News and BigBank, and if that fails, you can try an…

The difference is that the password works as a shortcut for situations where the email approach adds lots of friction (working on a "guest" device, latency, the entire world spam countermeasures). Friction is very much acceptable for password recovery (arguably even desirable), but not so much for conventional login. A nice middle ground would be allowing to opt out of passwords, for people who are happy with the com…

> The difference is that the password works as a shortcut for situations where the email approach adds lots of friction (working on a "guest" device, latency, the entire world spam countermeasures). Friction is very much acceptable for password recovery (arguably even desirable), but not so much for conventional login.

That's a general response to the question of why passwords might be nicer than email OTP.

But it doesn't answer my question - namely, any security problems that might be attributed to email/SMS OTP also exist almost invariably with almost all in-the-wild password implementations, and therefore, isn't email OTP only more secure than password plus an email OTP called "password reset". This question is purely a rebuttal of the claim that passwords are more secure than email/SMS OTP.

In the wild, there are a few sites where an email account, and therefore password reset, is optional. Hacker News and Reddit are examples. But these are in the extreme minority, and almost never secure anything worth securing. Bank accounts are another class of exceptions, where they secure something so valuable it is worthwhile going through a human verification process before you can do a password reset. But almost everything else - online stores, newspaper comment columns, much social media, web apps used for work, phone apps that let you monitor your robot vacuum cleaner, email accounts - almost all of them expect you to have an email address and use it for a password reset

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#114

Earlier quoted context omitted.

I've experienced that too.

The issue isn't with the user's email. The issue is with the site's email provider. If the email server sending out the one time links is under heavy load or for some reason has a backlog, it may take a while for the links to actually get to the user. This usually happens because whatever service the site is using to handle sending out emails is under heavy load, having issues, or is rate limiting the site due to a s…

> The issue isn't with the user's email

As an email layman, I don’t fully buy this, can you explain? I’ve sent emails with multiple CC’s and most get it quick while one or two people have to wait for it to hit their inbox for multiple minutes. I assume they all leave my service at same time and the delay is caused by the receiving mail server.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#115
Really fascinating subject that I've been thinking about a lot lately. At $FewCosAgo, I inherited a codebase which used passwordless login via SMS. SMS has a ton of intrinsic security flaws because of SS7 so there are obviously risks with this method. But with that said, it worked very well for the exact same reasons email doesn't here: SMS delivers nearly synchronously, and it was rare to end up in a situation where the login text didn't send to a user. After going through the flow a couple of times myself, I was shocked at how much more I felt inclined to test my own software just because logging in was so much lower friction.

Regrettably, the issues with passwordless email/SMS login mean that for now, if there's no OAuth provider you can/want to use, the ol' password is probably still the best way to go.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#116

Earlier quoted context omitted.

How do you advise we handle email address confirmation and password resets?

Automatically expire the links

Apparently I completely ignored the first comment in the original post. Apologies.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#117
post #91

Earlier quoted context omitted.

> 1. Email delivery latency This is particularly true when the recipient has enabled Greylisting[0] and delivery has to be attempted multiple times (which is perfectly fine from the point of view of the RFC standards). In view of this, email delivery rather resembles real-world postal package delivery (and not so much the instantaneous delivery of, say, phone calls). [0] https://en.wikipedia.org/wiki/Greylisting_(ema…

Is it possible to solve by some kinds of warming up? AFAIK greylist is IP-based. We can send email at regular time so all the sender IP can keep in list. But email does has many uncertainty like spam detection and others to slow the process after SMTP server receive it.

How would that work? Send an email to every customer (domain, so pick a single customer at every domain) and send them an email with a fake login, or a note that says please disregard?

Aside from that being spam, it's also likely to get legit emails stuck in spam filters as people start marking them as spam.

Secondly, I think most of the largest providers don't really grey list any longer. They seem to have moved to inbound throttling. So your first email goes through but then if you send a rash of mail, you end up seeing the throttle on the back side.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#118

Earlier quoted context omitted.

I've experienced that too.

The issue isn't with the user's email. The issue is with the site's email provider. If the email server sending out the one time links is under heavy load or for some reason has a backlog, it may take a while for the links to actually get to the user. This usually happens because whatever service the site is using to handle sending out emails is under heavy load, having issues, or is rate limiting the site due to a s…

> The issue isn't with the user's email. The issue is with the site's email provider. If the email server sending out the one time links is under heavy load or for some reason has a backlog, it may take a while for the links to actually get to the user

That is not completely true. I've been operating my own mail server for almost a decade, since I am the only person using it the volume of email I send out is almost none.

I've observed on more then one occasion that sending an email to my gmail or my fathers gmail account can sometimes take 20 minutes or more to show up in gmail inbox although I know that google accepted the email as soon as it was sent.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#119

Earlier quoted context omitted.

What other problems do you face with a dedicated IP?

Not MailGun, but we have 3 dedicated IPs with SendGrid and one problem is that there are spamlists and ISPs that block or mark down IP blocks owned by SendGrid so you get no real advantage from the dedicated IP. I wish you could "bring your own IP" to these services.

Heh, it would get tagged as a sendgrid ip after a few transactions.

Re: Ask HN: Why aren't one-time sign in links more popular for authentication?

#120
Because it's awful. A normal flow for me is credentials stored in browser/password manager. Login is more or less seamless, and typically takes under a second.

OTP login is multiple steps, involves me doing a copy/paste (or remembering the code), and requires a mandatory delay while I wait on the email. If I wanted to login incognito, or in a different browser, I may have to copy/paste the URL etc.

A better question is why anyone uses them at all given how bad they are. I've stopped using at least one site because it exclusively uses OTP links.

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