In password security, the longer the better. With a password manager, using more than 24 characters is simple. Unless, of course, the secure password is not accepted due to its length. (In this case, through STOVE.)
Possibly indicating cleartext storage of a limited field (which is an absolute no-go), or suboptimal or lacking security practices.
I once registered an account with a random ~25 characters long password (Keepass PM) for buying tickets on https://uhuu.com.br/
The website allowed me to create the account just fine, but once I verified my e-mail, I couldn’t log into it due to there being a character limit ONLY IN THE LOGIN PASSWORD FIELD. Atrocious.
EDIT: btw, the character limit was 12
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It’s pretty stupid because the longer the password the more secure it is.
I understand a cap of like 64 characters or something to keep storage space down for a company with millions of users. other than that it doesn’t make a ton of sense.
That is a huge red flag if ever given as a reason, you never store the password.
You store a hash which is the same length regardless of the password.Youre right lol. I forgot that hash lengths are different from the actually password length.
You never store passwords. They should be hashed and salted.
The cap should actually be due to the hashing algorithm. Every password should be the exact same length once it is salted and hashed, so the actual length of the password doesn’t make a difference in regards to database size. The hash will be a set length, so the storage requirements will be the same regardless. Hashing algorithms have a maximum input length. IIRC the most popular ones return a result of 64-255 characters, and cap at 128 characters for input; Even an input of just “a” would return a 64 character hash. But the salt is also counted in that limit. So if they’re using a 32 character salt, then the functional cap would be 96 characters.
Low character caps are a huge red flag, because it means they’re likely not hashing your password at all. They’re just storing them in plaintext and capping the length to save storage space, which is the first mortal sin of password storage.
I’ve had this exact same thing happen.
I’ve also had it happen where you have the two fields to verify the password is the same. One had a maxlength set in it, and the other didn’t. I was for sure entering the same password and I was so confused until I opened up the dev tools and inspected the inputs.
I’ve seen this behavior too, I forget where. For me it was a bit easier since the fields displayed a different number of stars. I did spend too long trying to figure out how my password manager could be failing that way
Okay so I agree with you that a longer password is better but this in no way indicates clear text password storage.
Is the maximum 24 characters because their database column is a VARCHAR(24)? That’s one of the first questions that I thought of. Sure, it doesn’t guarantee plaintext, but it’s a indicator that it may be stored plaintext, considering hashing doesn’t care about length. Or at the very least whoever has had eyes on this code doesn’t know shit about security, which makes me less confident in the product as a whole.
The only reason I can think of to have a maximum would be to save on bandwidth and CPU cycles, and even then 24 characters is ridiculously stingy when the difference would be negligible.
Oh look, a free account!
bcrypt hashes only the first 72 bytes. 24 characters is the max amount of 4 byte UTF8 characters when using bcrypt. Which is stupid because UTF8 is variable, but still, it’s a possible explanation.
A reason reason to switch to argon :)
Cryptographic hash functions actually have fixed runtime too, to avoid timing-based attacks.
So correct password implementations use the same storage and cpu-time regardless of the password.I figured it was about the time spent transmitting. But the password should probably be hashed before sending as well as upon arrival at the server, correct?
It isn’t usually. If it was, the server-side function wouldn’t need a constant runtime at different-length inputs since the inputs would not have differing lengths.
The problem with client-side hashing is that it is very slow (client-side code is javascript (for the forseeable future unless compatibility is sacrificed)), unpredictable (many different browsers with differing feature-sets and bugs), and timing-based attacks could also be performed in the client by say a compromised browser-addon.
For transit a lot of packaging steps will round off transfer-sizes anyhow, you typically generate constant physical activity up to around 1kB. Ethernet MTU sits at ~1500 bytes for example, so a packet of 200 bytes with a 64 char password or a packet of 1400 bytes with a 1024 char password containing some emoji will time exactly identically in your local network.
I would have thought the opposite. I remember having a familiar conversation: “we need a sanity check in the password: what would no sane person do?” I believe we cut it off at 64 characters, but I can see someone thinking 24 is kore than enough, if they’ve never used a password generator.
It does. If you hash the user passwords, which you should, the hash is always the same length and it’s thus irrelevant how many characters the user’s password consists of.
Now, it’s not certain though, which wasn’t claimed either, because the front end developer might have other reasons for setting limits. The backend shouldn’t care though.
The backend should care though. Even if strings can have an unlimited amount of characters, you don’t want to go and hash a gigabyte of data. In lower level languages you don’t have magic strings either so you might do something like
char password[64].There’s many reasons to limit raw password length. Not many good ones to have it as small as 24 (or even 64) though.
There should be a limit. It should be so high that we never hear about it. 1MB for example.
Exactly. The tax on hashing the password can’t be ignored and if you’re doing this enough times it can kill a system. 24 characters is too low. I’d say 100 characters is enough for most use cases. 1024 if you’re feeling 1337.
Sure, but when we talk about the computation then the number of rounds is by far the more important factor compared to password length.
The discussion is about whether 24 characters indicate cleartext though - not whether password lengths should be in the gigabytes.
Seems reasonable.
I agree you might have threat actors looking to DoS your system if there’s a publicly exposed REST endpoint accepting gigabytes of data. That has nothing to do with the discussion on password hashing though.
The claim was that a limit on passwords implies plaintext storage. It doesn’t. There is no such thing as unlimited on computers.
The claim was that a limit on passwords implies plaintext storage.
quoting the post:
Possibly indicating cleartext storage of a limited field (which is an absolute no-go), or
It was not a claim that it certainly is plaintext storage. It was claimed to be a possibility. AND provided an alternative explanation.
Maybe you’re more confident than me in good practices and implementations across all services. But I’ve seen enough to know that’s not always the case. It’s good to be skeptical on anything related to security.
but this in no way indicates clear text password storage.
It does.
No it doesn’t.
It does.
/80’s hacker turned Software Engineer turned Cybersecurity professional
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Don’t worry, I’m autistic myself and understand how difficult it can be to parse “it’s thus irrelevant how many characters the user’s password consists of” to mean something besides “all implementations must accept an unlimited amount of characters”.
I do believe the point was understood by the general reader however.
What an awful thing to say. Go question your motives.
Curiousity: Could you please explain what was awful about the comment you responded to?
For context, I’m also autistic.
There is no good reason so send the passwors itself to the server. Send the hash and you will have a fixes length of data to send anyway.
And even if insist in sending the password over the wire, there is no problem on the backend to handle longer passwords than that, so that no one will run into a limit in practice. We’re talking about bytes here, not even a kb.
Proper hashing of a password includes a salt that should be kept private. This means the password should definitely be passed to the server in plaintext. The server adds the salt to the password, then hashes it.
This adds more protection should an attacker somehow manage to get access to your hashed passwords. Even if they identify the type of hashing mechanism used it will prevent the use of rainbow tables, dictionary attacks, etc. against the hashes.
While I’m not arguing for doing the crypto client side, the salt isn’t needed to be private - only unique.
It definitely needs to be private. If an attacker can obtain both the password hashes and the salt(s) (via the same database vulnerability for example) then they have everything they need to run offline attacks against the passwords.
No, it most definitely does not need to be private. The idea with salt is to invalidate rainbow tables. If you’re “keeping it private” it’s just another password.
The salt and the password (or its version after key stretching) are concatenated and fed to a cryptographic hash function, and the output hash value is then stored with the salt in a database. The salt does not need to be encrypted, because knowing the salt would not help the attacker.
If that were the case you could still hash it on the client side, forcing it to be a certain size and then hash it again on the server with the right salt. I don’t think there’s a real disadvantage to hashing a hash.
you absolutely should not be hashing client side. You need to securely transmit the password to the server where it is hashed. You do not want clients knowing /how/ the password is salted/hashed. this lowers your security overall.
There’s some software that hashes the password clientside before sending it, sure. But it still should be hashed serverside too.
If the server hashes a hash, the plaintext password’s length is still irrelevant
That’s not true. There’s limits everywhere.
Plaintext password (693 chars):
“hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2hunter2”Clientside SHA-512 hash (64 bytes):
7399ed78effda820b2187bc70f0549dd67f6846c595f944d198a1f1136cd0ab91119d6f208a34b4419e969b9ffb326d3786cecb90828f0ab36a5e3835558740c— Client sends 64 bytes to the server —
Serverside SHA-512 hash (64 bytes):
25293199e10af10e8a20f4ab38abccd2cdccd762d8cba2ed4871a2aea8fe6d9ffcc54cfe1c9cbd03245bfd2f0ee1039f06083b7bcbefd91b7fcbba182d588983At no point the server has to deal with the length of the plaintext
It could be an older codebase that’s using an inline encryption algorithm as opposed to a hash. Using an encryption algorithm with a private key would result in varying length outputs.
That’s the same as “cleartext” for someone who works in security though, since that means anyone with the private key can decrypt the password.
Password hashes always have the same length.
Why is there a limit at 24? It may be an arbitrary limit set, or it may be because they don’t store more.
I heard some banks encrypt single characters of the password separately (no idea how that would be safe) they often ask to provide random characters from the password instead of the entire password.
My bank only accepts up to 20 characters. It doesn’t validate it… The login page simply ignores all characters beyond 20th. So I didn’t even know that it cut my password until I tried to log into the mobile app, which replaces the last character when you type more than 20… that was confusing 20 minutes when I didn’t know why I can’t log into my mobile app.
What would be the other reason for a password length limit so low ? I could understand limiting to like 64 characters but 24 sounds low.
What’s more frustrating is when the password creation page is silently cutting off too long passwords and don’t inform you about it.
There’s a site I use that does that on the password reset page, but not when logging in. So when using a long password it’s as if the reset never works. Took me ages to figure out what was going wrong.
Back in the day, long time ago, Unix would do that, and limit user silently to 8 characters.
Which then wasn’t great, but a good password would be hard to break even at only 8 characters with equipment of the time.
We would do a cracking test against the user passwords periodically and ding users who got cracked. Well one user was shocked because they thought their 16 character password was super secure and there’s no way we would crack it. So we cited her password and she was shocked she went through so much trouble only for the computer to throw away half her awesome password.
I have a “cuts off special chars, wtf” somewhere in my password store.
Oh, I hate this one
This shit pisses me off so bad. I had an identity theft a few years back, took ages to undo, and my credit score is still impacted by it. At the time I moved to a password manager and all my passwords are 31 characters of garbage. I’ve got several, highly sensitive accounts that my passwords don’t work for, in fact one a bank, until fairly recently, had repurposed a phone number field in the DB so passwords were limited to 10 characters numeric only (I managed to get one of their IT folks on the horn to explain why the password was so awful).
I cannot believe we live in 2025 and we still haven’t figured out passwords.
My bank forces a 6 digit PIN as a password.
Their 2fa is also email or text only.
At least we can set a unique username?
Yeah, I’m up to 40 hide my addresses for that same reason. Figure if the password sucks, at least the email can be unique and obscure.
168! Don’t hold back - everything gets a unique email address, a generated password, unique username and profile info.
It’s only the damn phone number that can be used to connect my data. Can’t do anything about that.
Meh, if they lock you out after X attempts, then 6 digits is fine. Hell, even 4 digits is fine if they have a lockout-policy.
Do they have a limit on attempts?
So long as attempts aren’t per IP and or ipv6 isn’t allowed
We have figured out passwords. Management hasn’t figured out allocating resources to security, and governments haven’t figured out fining the crap out of such companies.
all our banks and government systems and may online services work on a governments own 2fa, and there are several variants. They are linked to phone and require inputting Pins. Very comfortable, very secure and very convenient. Also very fast.
Don’t get me wrong, there are systems that work. I built up a very successful smart card based system many years ago after a failed audit. I initially hated the idea but in the end we built a crazy secure environment that was very easy to use and maintain. That project is long since obsolete but after doing that one, over a decade ago, I figured things were headed in the right direction.
I think I’m extra sensitive right now because my aging mom has made the issue acute. She’s not the same as she was a few years ago and helping her with all her online accounts has become a nightmare. It’s just too complicated for many folks.
Your password MUST contain big and small letters, and contain at least 1 number character and 1 spacial character, it MUST be 8 characters long, and it MUST be typed on a German Cherry keyboard between 8-9 PM, using ONLY 1 finger while blindfolded and listening to ABBA music. BUT NO SPACES ALLOWED!!!
This is because of something called entropy we never even read about so we have zero understanding of it. Of course combined with lousy programming, so safety is all on you.Making all these possibilities OPTIONAL would actually make for safer passwords (higher entropy), as would using multiple words separated by spaces. The only meaningful way to accept a password would be to test it against common bad passwords, and test the entropy to determine acceptable levels. There is no good reason a password couldn’t be 10 words and at least 127 characters. There is no way that should stress a properly designed modern system.
You have described all of the guidelines that NIST, Microsoft, GCHQ and a few other institutions now recommend for password security.
And yet I still have to have this argument with so-called security engineers and my favourite, compliance officers.
the guidelines that NIST, Microsoft, GCHQ and a few other institutions now recommend for password security
Because they are morons that don’t understand entropy.
Requiring at least 1 number increases entropy less than simply allowing the use of numbers, and then recommending it.
But most password queries are lousy at describing what’s allowed when creating it, and they generally don’t describe it at all when you enter it for access.
The second part can be crucial for remembering exactly how the password was created, because what is now required, used to often not even be possible to use!
you forgot that you can only use a selection of special characters from a pre approved list of 10.
Had that yesterday.
“Must use special characters!”
“Okay, no problem. Here you go.”
“Not that one! It’s too special!”
“Dude, I haven’t even touched extended ASCII yet.”
A pre-approved list of 10 which THEY DON’T EVEN TELL YOU WHAT THEY ARE
I love when there are so many rules that my first few randomly-generated passwords are rejected.
Even worse, when you can’t figure out why, or how to configure the generator, then end up having to type your own anyway
I like the ones that just tell you your password strength.
Subtle shaming of bad passwords without giving bad actors hints as to what the minimum (and thus most likely) password is.
genuinely, whats up with not being able to use spaces?
I’ve had a case in the past where I reduced my password to the limit, but after account creation, I was not able to log in.
Turns out they had an off-by-one issue, and a password with a length slightly below the limit worked fine.
I once got locked out of an HP printer because it chopped off the last few characters of a password. Only figured it out because somebody had made a comment online about password length
Experienced a site some years ago that let me I put however long password I wanted (my default is 52 in my password manager), but turns out it only used the first 20 or so.
My mum told be the other day she logged onto a new bank, gave it a 12 character password then couldn’t get back in after. When she got through to their customer services they said that it was an 8 character password limit (!), but it just never said on the register screen.
Yeah, I’d be doing that bank if there’s any choice.
Edit: Leaving (my attention got taken away as I posted)
Either this is some new slang I’m not rizz enough to understand or one of us had a stroke.
He just wants to have sex with the bank.
No cap
Tain planet, he’s our hero.
Maybe that’s security by obscurity. Or security by confusion. /s
Microsoft does this to our users at my job. They go to charge their password and it won’t accept it but won’t tell them what the requirements are. “Your password doesn’t meet our criteria.” Okay, so what are you looking for???
Worst is that there seems to be a soft block at some point and instead of telling them that, it shows this dumb error instead over and over again no matter what password they choose.
so secure, no one can get in, even her!
Ah must be my bank. Same.
We have a customer, a big international corporation, that has very specific rules for their intranet passwords:
- Must contain letters
- Must contain numbers
- Must contain special characters
- No repeats
- Passwords must be changed every two months
- Not the same password as any of the last seven
- PASSWORDS MUST BE EXACTLY EIGHT CHARACTERS LONG
I can only assume that whoever came up with these rules is either an especially demented BofH, or they have some really really weird legacy infrastructure to deal with.
No repeats??? Like, you cant have ‘aaaa123@’ as a password?
You’re just making it easier to brute force…
I am a designer, but I once did a project with a very very major and recognizable tech corporation that, no joke, implemented an 8 character limit on passwords for storage reasons.
This company made in the tune of tens of billions of dollars per year, and they were penny-pinching on literal bytes of data.
I can’t say who it is, but their name begins with ‘M’ and ends in ‘cAfee.’
If password length affects storage size then something has gone very wrong. They should be hashed, not encrypted or in plaintext.
I worked in IT for a big national company for a short time. Passwords rules were : at least 8 characters, at least one uppercase letter, at least one number, change password every 2/3 months and different than the 3 previous ones. Several workers had a post-it on the screen with the 4 passwords they use. One of them had name of child and year of birth, I don’t know if it was his children or his relatives’ children too.
How about creating a new account, letting bitwarden create a password, only for them to send me a clear text copy of that passwod in their confirmation email…
Here’s your password, remember to write it down on your password post-it!
i thought that practice died like 20 years ago
That means the breach is imminent, but at least you won’t need to worry about other accounts when it happens. Just be sure you don’t give them any kind of PII or financial data to save. No, you can’t save my card data to make shopping easier, because you’re almost certainly going to have a data breach next month, and drag your heels about disclosing it, giving hackers plenty of time to commit a bunch of fraud using all of the cards on file.
friendica does this.
funniest experience that ive had is that i made a psn (playstation network) account with a 64 (iirc, might have been 32, dont remember) character password. That worked making the account on my PC on their website. Never was able to log into that account on my playstation tho and the error message was just some generic error. Support didnt know what was going on and i didnt either until it dawned on me. The password was too long for the console. Changed the whole thing to a shorter one and now it works everywhere. Used to work on their website, not in the app, not on console. Fun.
Don’t worry, pretty soon they will just block password managers from autofilling fields on their login page so that you HAVE to remember your password! Then you’ll be happy it can’t be that long, you can only fit so much on a post-it note on the side of your monitor
/s
EDIT: I think there should be a law against blocking password managers for filling in fields. Any brute force bots are going to submit HTTP requests directly anyway; no one is hitting the DOM to do that
think there should be a law against blocking password managers for filling in fields.
I’ve never heard of anyone trying to do that. I couldn’t even imagine how a website could detect a password manager.
I’ve seen a couple of times. It’s the same ones that block copy/paste on password fields. The workaround is to write a short python script using pyautogui or similar to “type” out the clipboard content.
I’ve had banks do it in the past. It’s not that they can “detect” the password manager, they just use a method that’s incompatible with them.
They have a fake input field and capture keypress events via JavaScript directly from the dom, then just make it look like you typed in to the input field. They don’t read the password from the input field, they build it up in memory from those key press events.
It also completely breaks accessibility software, which is the main reason I think the industry moved away from doing it for the most part.
My favorite is when they don’t have this check, but silently slice the string to meet the requirement, so that you can’t login with the original password the next time.
Wells Fargo used to do this. They cut my 16 character password to 8 and negated capitalization. Which is why I don’t use them anymore
amazon also had it a couple years ago
My bank used to do that back in the early 2000’s, I moved banks.
Metro Bank did something like this to me.
Recently had a password that was acceptable for the account creation page on the website but too long for the login screen in the mobile app.
Took me a while to figure out that pasting into that field was just quietly dropping characters.
What is worse is when it does not quietly drop any characters and you have to keep resetting your password.
When both the account creation and the password reset fields accept more characters than the login this is an endless loop!
until
stackemail inbox overflow /s
c/passwordtoostrong
There should be a limit to prevent DoS attacks but really it should be like 1M characters or something.
No, there should be no limit. The password should be salted and hashed stored on the server side they should be uniformly like 256 or 512 characters behind the scenes no matter if you send it 5 characters or 50,000. The password that is stored is just a mathematical representation of the password.
As far as DDOS, It doesn’t matter what the limit is, you can send them millions of characters rven if they have a limit. If you’re going to DDOS you’re going to just use SYN flood, pings, for all of the matters you could send headers.
Not DDOS, DOS. You can often crash an unprepared server with one request by telling it to hash more data than it has memory for. See this blog post for a well-known web framework. Let’s say I just sent it a 10GB password, it still has to process that data whether or not the hash eventually shortens to the database field length.
Though it could also amplify DDOS. Allowing 72 character passwords lets a DDOS be three times rougher despite being a seemingly modest limit for a single request.
If a password/passphrase is 24 characters, then any further characters have no incremental practical security value. The only sorts of secrets that demand more entropy than that are algorithms that can’t just use arbitrary values (e.g RSA keys are big because they can’t be just any value).
Just another in a long list of decisions Django made that makes me dislike it.
Let the client hash the password to reduce it. then enforce the hash length as the password length. It’s transparent to the user and doesn’t look like a pile of bad ideas.
So I just went through something similar with a security team, they were concerned that any data should have limits even if transiently used because at some point that means the application stack is holding that much in memory at some point. Username and password being fields you can force into the application stack memory without authentication. So potentially significantly more expensive than the trivial examples given of syn and pings. Arbitrary headers (and payloads) could be as painful, but like passwords those frequently have limits and immediately reject if the incoming request hits a threshold. In fact a threshold to limit overall request size might have suggested a limited budget for the portion that would carry a password.
24 characters is enough to hold a rather satisfactorily hardened but human memorable passphrase. They mentioned use of a password manager, in which case 24 characters would be more entropy than a 144 bit key. Even if you had the properly crypted and salted password database for offline attack, it would still be impossibly easier to just crack the AES key of a session, which is generally considered impossible enough to ignore as a realistic risk.
As to the point about they could just limit requests instead of directing a smaller password, well it would certainly suck of they allowed a huge password that would be blocked anyway, so it makes sense to block up front.
Why not client side hash? JS is more than capable.
Sure, you could do something like that to normalize all manner of passwords to a manageable string, but:
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That hash becomes the password, and you have to treat it as such by hashing it again server side. There’s a high risk a developer that doesn’t understand skips hashing on the backend and ends up insecurely storing a valid password for the account “in the clear”
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Your ability to audit the password for stupid crap in the way in is greatly reduced or at least more complicated. I suppose you can still cross reference the password against HIBP, since they use one way hash anyway as the data. In any event you move all this validation client side and that means an industrious user could disable them and use their bad idea password.
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if you have any client contexts where JavaScript is forbidden, then this would not work. Admittedly, no script friendly web is all but extinct, but some niches still contend with that
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Ultimately, it’s an overcomplication to cater to a user who is inflicting uselessly long passwords on themeselves. An audience that thinks they need such long passwords would also be pissed if the site used a truncated base64 of sha256 to get 24 ASCII characters as they would think it’s insecure. Note that I imply skipping rounds, which is fine in such a hypothetical and the real one way activity happens backend side.
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