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 used 20 for a bank. the website havent told me it was too long just clipped off 2 and accepted the rest. not even the banking support was able to help me. took me a few days to solve this by accident.
This shit always pisses me off. I’ve encountered it in like 2-3 places over the years since I started using a password manager, and every time it’s so frustrating and hard to figure out.
That must have been frustrating. How many times did it lock you out from trying again?
I don’t have it in me
If I have to create a password Ill need to remember and don’t have access to my password manager for whatever reason I have a long phrase that’s my go to but I have a system about adding numbers and characters to it based on the context of the log in. Sites with character limits really fuck that up.
One of the accounts that I have to use at my job is like this but much much worse. It only accepts letters and numbers, no capitalization, no symbols and can only be 8 digits long maximum. It’s like they want to account to be easy to compromise.
That sounds like the limitations of an ancient mainframe system. If so, then someone trying to brute force their way in would be more likely to crash the system instead.
At least they tell you. I signed up with websites that just cut the password after the 12th character. No way of signing in with the password again (not without trying a couple of times, at least)
when you varchar(24) and forget about the hash
This seems to be very common still
Some people even suggest typing a longer password over a simpler one with more special characters. It’s harder to brute force.
I thought the use vocabulary lookup tables effectively nullifies the entropy benefits, if everyone started using phrases as password
I don’t know enough to say how accurate the numbers are, but the sentiment stands - if it’s a password you’re memorizing, longer password will probably be better.
That’s not even the case though. Using a memorized passphrase that can be broken down into individual words is susceptible to dictionary attacks provided you know what the length of the password is. You can algorithmically sort away swathes of the dictionary based on how many likely word combinations exist before searching unusual word combinations. The thing is, passwords suck. It doesn’t matter how long the password is, if someone wants in, they’ll crack the password or steal it via some other means. Instead of relying on a strong password, you need to be relying on additional proof factors for sign in. Proper MFA with actual secure implementation is far more secure than any password scheme. And additionally, hardware key authentication is even more secure. If you are signing into an account and storing important data there, you do not want to rely on passwords to keep that data secure.
The reason for the character limit on passwords is often to prevent malicious attacks via data dumping in the password dialogue box. Longer numbers take more CPU cycles to properly salt and encrypt. Malicious actors may dump as many characters in a password system as they wish if they wanted to take down a service or at least hurt performance.
Additionally, even if you just used lowercase letters, an 18 character password would take 12 RTX 5090s approximately 284 thousand years to crack according to the recent Hive Systems report.
24 characters is more than enough to be secure as far as passwords alone go. Just know that, nobody is out here brute forcing passwords at any length these days, there are infinite more clever ways of hacking accounts than that.
You’ve got to stop all those who put: abcdefghijklmnopqrstuvwxyz
That’s my password for most things, any hackers die of RSI before they get in.
It’ll be caught by a dictionary attack. at least do something to break up their sequential order.
Being regected for being too long. What a conundrum.
I like it that the site says the max length…this is not common. I wish it was.
The problem is a password hash is a fixed length regardless of the password, so if this is implemented correctly there is no need for a maximum password length. These things raise my security flag because it makes me think they are storing the password in plain text instead of doing proper practice and storing the hash only.
What’s the point? no one is brute forcing a 12-15 password if the login system has ANY login attempt protection anyway.
This seems like one of the extreme overkill things…
That doesn’t help if someone got a list of their hashes somehow. Then an attacker can use their own system to crack them.
And that’s if they aren’t just storing the passwords as clear text to begin with, which length limitations are often a sign of.
Such a small max length is a good indicator they aren’t handling passwords correctly. A modern website should be able to send and hash kilobytes of text without the user seeing a significant delay. Having a max size like this sounds like they are storing the password as text instead of a hash.
Or some dumb project manager said passwords longer than 24 characters look bad in the UI and wanted the limit.
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
PayPal did the same. Registration took 40 characters, login only half of that. Editing the login form didn’t work unfortunately.
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.Although at some point you’ll get collisions, but I don’t think that’s actually an issue. It still equally hard to guess a password from the hash, there will just be some solutions that are much longer than others.
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.
You can easily get the hash of whole files, there is no input size constraint with most hashing functions.
Special password hashing implementations do have a limit to guarantee constant runtime, as there the algorithm always takes as long as the worst-case longest input. The standard modern password hashing function (bcrypt) only considers the first 72 characters for that reason, though that cutoff is arbitrary and could easily be increased, and in some implementations is. Having differences past the 72nd character makes passwords receive the same hash there, so you could arbitrarily change the password on every login until the page updates their hashes to a longer password hashing function, at which point the password used at next login after the change will be locked in.
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 good reason to switch to argon :)
To be fair, 24 is still a secure length for a password, and will probably be for another 5-10+ years.
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
deleted by creator
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.
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.
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.
The salt is specifically to invalidate pre-generated rainbow tables, and doesn’t need to be kept private. It only needs to be unique.
The attacker generates rainbow tables by running common passwords through known hashing algorithms. So I run “password1” through a bunch of different algorithms, and save the results of each. Notably, generating decently large rainbow tables takes a lot of time, processing power, and storage space. Because you don’t just use common passwords; You’re basically running a brute force/dictionary attack on your own computer’s hashing algorithm.
Now if a database is unsalted, I can search for matching results against my rainbow table. When I see a match, it tells me both which users had that password and which hashing algorithm they were using. So now I can narrow down my focus to only using that algorithm.
But if a database is salted, all of my pre-generated tables are useless. Even if someone used “password”, it won’t match my rainbow tables because the hash was actually fed “password{hash}” instead. And even if multiple users used “password”, each salt is unique, so I don’t see a bunch of repeated hashes (which would point to those accounts using the same password). I would now need to generate all new tables with the salts I stole in order for my rainbow tables to be usable again. And even then, I’d need to repeat that table generation for every user.
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.
If you’re doing hashing and salting on the client then yep it’s useless, no difference to just using a hash output as a password.
If on the other hand you’re doing a zero-knowledge password proof method then it’s quite secure. As the password is never transmitted over the network, not even the server knows what it is, but can still verify the user has the correct one.
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.
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.
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’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
