Avoid crypt_blowfish (crypt function) until patched

A serious flaw was discovered in crypt_blowfish that severely weakens users passwords. It is easy to fix but until a patch is released, avoid it. If its already implemented, find a way to update users passwords with new hashes. Just to make it clear, a password of “1234” with be the same as “4” when hashed with crypt_blowfish.

See: PHP: crypt - Manual
And: A hole in crypt_blowfish [LWN.net]

Update those password hashes that are using crypt_blowfish.


Can’t say I’m suprised. Is this the C sign extension bug, the bitwise-overflow bug, or just the fact that it has a pass to repeat ratio in excess of 1000:1?

Actually, your example says it’s the last of those. It’s why blowfish (and even twofish) after aren’t even as good as SHA256… and yet you hear nowhere as many people pissing on blowfish as you do SHA.

I must say its interesting that no one discovered this before now. We have never used Blowfish in any environments as imo there is better alternatives, but it would be interesting to have known if it only older systems have been affected by this, or if any newer systems has been using it as well.

Just a side note, Blowfish/Twofish is encryption algorithms while SHA is a hashing algorithm. While I understand your point your trying to make, the two cant be compared.

It sounds like only the last character of passwords was being encrypted there, I’m surprised this wasn’t detected earlier by someone.