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Comment by txcwpalpha | Hacker News Reader

> The stolen data contained names, email addresses, scrambled password (believed to be hashed with the MD5 algorithm and salted)

This is absolutely atrocious if this is the case. MD5, even with a salt, can be cracked in a matter of seconds even with the most basic hardware. MD5 hasn't been an acceptable password hashing algorithm for at least a decade now, and StockX was created in 2015, long after the creators should have known better (sadly, despite this, an absurdly high number of companies still use MD5 for pass hashing).

These passwords, hashed with MD5, might as well be considered to have been stored in plaintext.

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Given that data, doesn't their attempt to call this "system updates" constitute a violation of California's data breach notification laws? https://oag.ca.gov/privacy/databreach/reporting

Oh man this is an interesting grey area. If the data was “encrypted” then they aren’t required to notify unless the encryption key is reasonably believed to have been acquired by the hacker.

I don’t know anything about MD5 or what makes it vulnerable but if StockX has no reason to believe the hacker acquired the key they could certainly make the argument they had no notice obligation.

Reading the statute (and assuming MD5 is as weak as everyone here says) I would say it falls outside the definition of “encrypted” but it really kind of depends on how honest the security engineers were with the lawyers.

I’ve never thought to ask “how encrypted?” when dealing with a breach but I definitely will now.

The non-password data was not encrypted, so is definitely a breach of California law.

Ahh well then it’s definitely not grey. And serves me right for scanning the comments here and not actually reading the article.

MD5 is not an encryption algorithm. There is no key!

Sounds alarming, but not true. If you don’t know the salt, you are not cracking an MD5 password on basic hardware. You are probably not cracking the password in any reasonable time, period.

And when you have a unique salt per user, that’s basically game over.

Usually the salt is stored along the login and password.

That’s not on the list of things stolen, so the passwords are safe. The salts were kept elsewhere, as they should be.

Do you have some insider information, or where are you getting this? If the hackers were able to steal all of the other login information, the salts were almost certainly stolen along with the hashes.

The article doesn't mention customer id and account creation date, though these records were almost certainly along the login and passwords also. It's general news article.

Why should salts be stored elsewhere? If you have some high-security other storage, why don't you store the password hashes there?

Look up benchmarks for cracking MD5 hashes. You can crack an MD5 hash of an average length password (and StockX only requires an 8 character password), even with a salt, within seconds with a single consumer grade GPU. A hacker group with any serious setup for hash cracking has almost certainly already cracked most, if not all, of these hashes.

Unless you presume that you know the salt your comment is utter nonsense.

The fact that the article says “believed to be” strongly suggests that things are not as simple as they’re “believed to be”, because if the passwords were easy to crack that’d be trivial to prove.

If the passwords have leaked it's safe to assume the salts have, typically they're stored side by side.

If the hash has been leaked then why is there reason to believe the salt _hasn't_ been leaked?

>Unless you presume that you know the salt your comment is utter nonsense.

Usually the attacker will also know the salts in a breach of this type, unless the company did something clever with the salts (doubtful since they used MD5).

The fact that the article says “believed to be” strongly suggests that things are not as simple as they’re “believed to be”, because if the passwords were easy to crack that’d be trivial to prove.

We don’t know how the passwords are hashed. All we have is a journo guessing.

Show me the benchmarks.

https://gist.github.com/epixoip/a83d38f412b4737e99bbef804a27...

Looking at phpass (one of the md5 algorithms), a high-end GPU can do 7M hashes per sec.

nowhere in these benchmarks anyone said the MD5 were salted. am i reading it wrong?

Unless you're operating under the (likely incorrect) assumption that the salts aren't leaked than salting the password doesn't matter for attacking a single user - it just means you can't reuse your results for other users.

If StockX was using phpass (which is a KDF that uses MD5 as a base but adds multiple permutations on top), it is quite a bit safer (but still not recommended and these hashes should be considered to be compromised).

The bigger issue is if they were actually using raw MD5 (which is sadly quite common), which is benchmarked at 25 billion (with a B) hashes per sec per GPU.

In 2012: https://www.zdnet.com/article/25-gpus-devour-password-hashes...

That's 7.2 billion hashes per second per single Radeon GPU for md5. For 8 character password with numbers and letters that's 8.5 hours max and 4.25h on average.. The numbers only got better since then, I expect it's at least halved for this year's hardware. (edit: 1080ti does 32GHps, so yeah... make that 1h on average https://www.servethehome.com/password-cracking-with-8x-nvidi... )

Assumptions, not specified in the article:

- The salt is stored with the hash (this is a standard approach)

- It's only a trivial implementation with a single round of MD5. If they used multiple rounds or PBKDF1, then the hash choice doesn't matter as much.

Those time periods also assume that you're just blindly cracking every possible 8-character combination, but you don't have to do that. Running your cracker against a password list like rockyou will probably get you 90%+ of passwords cracked in less than one second per hash with that same hardware.

You need to update yourself on the vulnerability of MD5.

5 years ago, a run of the mill gaming PC could crack an MD5 hash in a reasonable amount of time. Worst case, you'd have to let it run overnight.

One of the big issues is collisions. You might not find the original key, but you'd find something that hashed to the equivalent output.

> Worst case, you'd have to let it run overnight.

AFAIK the best current preimage attack against MD5 gives you a complexity of 2^123.4. Even if you had every computer in the world working on this you'd never succeed.

>One of the big issues is collisions. You might not find the original key, but you'd find something that hashed to the equivalent output.

This is false. There does not exist a feasible preimage attack against MD5.

> hashed with MD5, might as well be considered to have been stored in plaintext.

Somewhere I used to work (now-defunct) stored DES-encrypted passwords with the key one column over in the database.

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