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Tell HN: Zoom truncates passwords to 32 chars
I tried to reset my password to a random alphanumeric string, 64 characters in length.
Initially, my password only had lower case letters and numbers. Zoom refused to allow me to use this string because it didn’t have any upper case letters. I figured they were only trying to help so I changed the last alphabet to upper case. Same error. I then thought that maybe they were expecting more than one upper case letter so I changed a few more letters in the second half of my password to upper case. Still the same error.
Annoyed, I changed the first few alphabets to uppercase and this time zoom accepted the new password.
I don’t recall what made me notice this but it turns out that zoom only takes in the first 32 chars of the password which it presumably stores in some hashed form in their backend.
While 32 chars is plenty long for a password, I just wish they’d mentioned this limitation on their website.
- randunel 7y agoThis used to be an issue with ebay.com back in the day. I used to be able to log in, but not change my password, because the length constraints were different.
- snazz 7y agoI imagine that this limitation is fairly common, although it probably wouldn't cost them any more to move to truncating at 512 characters or something like that. There has to be a limitation at some point to prevent denial of service attacks caused by hashing super long passwords. Maybe 32 characters seemed like a reasonable choice when they set the system up. I'm guessing that a large number of rounds of a secure hash function on 32 chars is more secure than a smaller number of rounds on 64 chars (given that most passwords are well under 32 characters long).
- londons_explore 7y ago> I'm guessing that a large number of rounds of a secure hash function on 32 chars is more secure than a smaller number of rounds on 64 chars (given that most passwords are well under 32 characters long). The number of rounds increases brute-force complexity linearly. Adding more characters increases complexity exponentially. Exponential is exponentially better than linear...
- snazz 7y agoBut if the average password length is 12 characters, does the maximum password length make any difference for the average user? More characters would certainly be better for those users who generate super long passwords, but for the service as a whole I would think that setting a lower maximum and more rounds would be better. Did I misunderstand something?
- deleted 7y ago[deleted]
- koolba 7y agoThat’s not as bad as Apple which silently removes white space within your password but doesn’t actually tell you it did that leading to locking yourself out after multiple attempts: https://news.ycombinator.com/item?id=13838342 https://news.ycombinator.com/item?id=13838342
- duxup 7y agoI honestly don't think I've used a space in a password before... not that it matters as far as the bug goes, but it just occurred to me.
- Dylan16807 7y agoAdding spaces to a jumble of characters is probably uncommon, but using something like a sentence as a password is very common, and also the main reason you want to support long passwords.
- rootusrootus 7y agoI would bet it has become much more common since correct horse battery staple.
- SwiftyBug 7y agoRelated xkcd: https://www.xkcd.com/936/ https://www.xkcd.com/936/
- hellcow 7y agoI was bit by this. Spent _hours_ on the phone with Apple support. They couldn't let me back in, and I was locked out for a week. They escalated to tier 2, then to engineering. It's really disappointing this wasn't fixed.
- satya71 7y agoIndeed, I spent hours trying to figure out what was going wrong.
- sneak 7y agoPayPal actually limits a password’s maximum length(!) to 20 characters. (I finally deleted my account there yesterday after close to 20 years; I should have done so years ago.)
- smartbit 7y agoWish Paypal would allow closing accounts if it is locked. Have one lingering around because my bank made a mistake and no way to access it without sending them tons of personal data. I created a second one which worked but not using it any more. Will follow suit and close it too.
- 0xFluegel 7y ago> While 32 chars is plenty long for a password, [...]. It might be plenty long for completely random characters, but when one uses a word sequence, the 32 characters are easily reached.
- tachyonbeam 7y agoWait a minute there young man, your password can only possibly be safe if it contains lowercase, uppercase, numeric and non alphanumeric characters!
- SwiftyBug 7y agoAnd god forbid that you repeat two characters in sequence
- davidg109 7y agoYou think that’s bad? A bank here in Canada, Bank Of Montreal, was using a maximum of 8 characters (and I believe no special chars permitted). Couldn’t use them anymore.
- 0xFluegel 7y agoMy german bank Haspa has a limit of 12. My guess for the reason -- apart from "we didn't have any problems, yet" -- is that part of the relevant infrastructure is ancient and uses a hardcoded max length...
- pdexter 7y agocharles schwab did that up to about 4 or 5 years ago
- meowface 7y agoHow recently were they doing that? That would be utterly insane in 2005, let alone 2020.
- roter 7y agoThey're now asking for new passwords: * minimum of 8 characters * one uppercase and lowercase letter * one number * one special character They should just allow any character instead of requiring characters. At least they allow longer passwords...
- moltar 7y agoTangerine uses 6 digits
- duxup 7y agoI had a bank do that to me too. I was logging in and sure I typoed my password but it worked. Then I tried typoing it again and it failed. Then I started to wonder ... yeah after like 8 characters it just didn't matter. I emailed them and did not get a response, but to their credit they fixed it within about a month. Maybe that was planned already but at least they fixed it.
- 7y ago
- psim1 7y agoWhat is your expectation for allowed password length and why?
- Hamuko 7y agoI find 64 characters a pretty reasonable expectation.
- wishinghand 7y agoIt’s not so much why the OP thinks they’re entitled to arbitrary password length, it’s that the UI/UX does nothing to inform the user of this. And also the bytes they save restricting password length to 32 instead of 128 or 256 would be a few dollars rounding error in the end of the Year budget.
- abfan1127 7y agoproper hashing yields no saving of bytes.
- wishinghand 7y agoYou're right, I forget about that. Which is why I'm not a backend programmer.
- masklinn 7y agoI fucking hope they don’t save any bytes doing that given that’d mean the passwords are stored in clear text. Though given what we’ve seen so far once people started taking a look that’s not out of the realm of possibility.
- deleted 7y ago[deleted]
- DangerousPie 7y agoI am really struggling to come up with a situation where this would actually matter. I guess if for some reason the first 32 characters of my password got leaked but not the next 32? But why would that ever happen, and who wouldn't change their password in that situation anyway?
- hsnewman 7y agoSo is today attack Zoom's security day?
- DangerousPie 7y agoFeels like this whole week has been attack Zoom week.
- Hamuko 7y agoIs today a day that ends in Y?
- dgritsko 7y agoNo affiliation with Zoom, but wow - the unrelenting torrent of negative coverage on HN over the last few days has been remarkable. It seems there's at least two or three negative articles on the front page at all times.
- asveikau 7y agoThere was plenty of criticism before. Remember they were the company that ran an unauthenticated web server bound to localhost so that any website could make requests to it and get the video stream. And they made it so that an uninstall wouldn't remove that. That was July. https://www.schneier.com/blog/archives/2019/07/zoom_vulnerabil.html https://www.schneier.com/blog/archives/2019/07/zoom_vulnerab...
- mkaymalright 7y agoExcuse me, what the f? Link? edit: Thanks
- jscholes 7y ago> unauthenticated web server bound to localhost so that any website could make requests to it and get the video stream I read the linked article. At no point did it (or as far as I can recall any of the coverage at the time) say that the video stream data could be accessed via the local web server. The problem was already bad; no need to make spurious claims to make it worse.
- asveikau 7y agoOk, maybe that was my slight misreading of the situation. It definitely involved use of the webcam without user consent, however. And an attacker could make you join a meeting that they control, effectively being able to watch and hear you.
- jscholes 7y agoOh absolutely. I'm not trying to downplay the serious nature of the vulnerability, particularly because it also lead to the possibility of remote code execution. Just want to keep the record straight that at no point did this vulnerability allow people to actively spy on your legitimate meetings.
- ZitchDog 7y agoIs anyone else getting tired of all the zoom hate? Yes, they have problems. But this company is holding the world together during a global pandemic. The service has worked great, and it must be a herculean effort to keep things running during all this. Zoom devs, if you're reading this, thank you. EDIT: I'm somehow being downvoted for expressing my gratitude to zoom for providing a service that is almost certainly saving lives. You're simply amazing HN, never change.
- dave5104 7y agoJust because Zoom's product has value, doesn't mean that its product's problems should be ignored.
- ZitchDog 7y agoI'm just asking for things to be put in proper context. These problems are only being highlighted because zoom is providing an extremely valuable service during an unprecidented time. How many lives have been saved due to zoom allowing people to socially distance better? I'd guess quite a lot.
- dave5104 7y agoVideo conferencing is a dime a dozen. There are so many other services, that I fail to see why Zoom should be given any sort of pass. Facebook is probably one of the best ways to connect to and stay updated with your extended family during a time like this. Should they be given a free pass for any scandals that come to light during the pandemic? Google is probably one of the best gateways to information about COVID-19. Should they be given a free pass for any scandals that come to light during the pandemic?
- ZitchDog 7y agoThere is nothing that offers a "brady bunch" view in as scalable way as zoom does. It's enabling types of interaction that aren't available on any other platform.
- hkchad 7y agoCan we PLEASE put a stop to the endless 'crap on zoom' articles on HN, this is getting out of hand.
- throwaway55554 7y agoI guess Zoom devs have never heard of "no artificial limitations". Yes, there are going to be limitations; no resource is infinite. But 32 chars is just too arbitrary.
- nickthemagicman 7y agoDo people make passwords longer than 32 chars? I was under the impression that with 16 random ascii characters it would take all of the computing power on earth until the heat death of the sun to crack it.
- rootusrootus 7y agoEver since correct horse battery staple, I'd bet plenty of people are going for long passwords. Though that might be offset by the surge in popularity of password managers.
- nickthemagicman 7y agoSeems like a series of words would be susceptible to rainbow table attacks and brute force via dictionary. I would toss in a numeric or a special character to really make it strong.
- efreak 7y agoThat's why salts are used
- benmmurphy 7y agoa lot of people use bcrypt and that has effective truncation at 72 bytes unless you are pre-hashing for longer inputs or doing something else non-standard.
- satya71 7y agoStill much better than most banks and miles ahead of ssa.gov
- lilott8 7y agoI have a sneaking suspicion that xfinity does this. When signing up they said there were no password restrictions. So I generated ~64 character password using my trusty password manager, and used that. Went to log in and couldn't, wrong password. So I changed my password, again ~64 characters, with the old trusty companion. Again, couldn't log in. Finally, I just changed my password to a randomly generated password of a commanding ~16 characters and haven't had a problem logging in since. I've spent more time than I care messing with my password on xfinity's site. There was exactly no scientific endeavor, and is purely conjecture. But it really feels as though there is some chicanery happening with passwords.
- sm2 7y agoI suspect these Zoom posts are primarily aimed at damaging the brand, rather than highlighting product flaws.
- thanatropism 7y agoThen, your user account is more "suspect" than the original poster's.
- deleted 7y ago[deleted]
- infogulch 7y agoI found out the main reason why passwords are limited length even when using modern hashing techniques. The problem is caused by the way multi-round password hashing algorithms are designed. Specifically, in each round, the full contents of the password is concatenated with the previous round's hash result as the input to the next round. This means that the processing complexity of password hashing is proportional to `number of rounds * password length`. Because the implementation has to tune the number of rounds to their authentication server's performance, and because the tuning is performed on "normal length" passwords, this opens the authentication servers up to a DOS attack by overwhelming them with very long passwords which is only a problem because password hashing has quadratic complexity thanks to this design. Thus, in response, administrators are forced (!) to limit password length just so their authentication servers can't be attacked. This design flaw (imo) could be pretty easily solved by hashing the user provided password once first, and then using that hash to concatenate each round. This changes the complexity to `number of rounds + password length` (note the "+" !). As a secondary benefit, the multi-round hashing step actually becomes constant time because all inputs are the same length! In fact, I wonder if the current design makes it possible to infer a user's password length from timing attacks on the authentication servers while a user is logging in. I've not got any satisfactory cryptographic reason why we still use this design for password hashing besides platitudes like "don't roll your own crypto", appeal to authority "It's been designed by the experts", or stupid reasons like "but network bandwidth!" -- as if an http authentication request that's 4kb is gonna slow down the network vs a 3kb request (and this is a worst case of a relatively huge 1kb password!). Availability is an important part of security, and sacrificing both availability (vulnerability to DOS) and security (admins forced to limit password length) seems like a doubly whammy argument against the current design.
- Sammi 7y agoEasy fix: Apply a regular ol hash function first, so the input to the the cryptographic hash function is the short'ish fixed length output of the regular hash function. A good regular hash function will preserve the entropy of a long input password, so it doesn't hurt, and it solves the problem you present. Bonus points for doing this on the client side so that you're not even using extra network bandwidth.
- rshnotsecure 7y agoApple does this too. Gmail is the best, something like at least 99 characters allowed.
- zelon88 7y agoI usually try to sneak comment characters and sequences from various languages into my passwords. That way if I sign up for a new account somewhere and the website gives me some really unexpected output back after I click "submit" I know that I probably don't want an account there anyway. Plus I feel like there's a chance it could screw up some script kiddies scripts if he gets my password into a wordlist for some second-rate hacking tool.