Re: kwallet crypto misuse

[gremlin () gremlin ru]

On 02-Jan-2014 09:15:15 +0100, Florian Weimer wrote:

> I just noticed this is now public:
> http://gaganpreet.in/blog/2013/07/24/kwallet-security-analysis/
> Short summary: kwallet uses Blowfish to encrypt its password
> store, and despite an attempt at implementing CBC mode (in a
> file called cbc.cc no less), it's actually ECB mode.

That's unpleasant, but not really a fatal issue...

> UTF-16 encoding combined with Blowfish's 64 bit block size means
> there are just four password characters per block.

But this is: any and all passwords, being used for encryption key
generation, must be hashed, then salted, then hashed again. SHA-256
may be a good choice for generating Blowfish 256-bit key this way.

> Encryption is convergent as well. This may enable recovery of
> passwords through codebook attacks. Should we treat this as a
> minor vulnerability?

Is it really minor?


-- 
Alexey V. Vissarionov aka Gremlin from Kremlin <gremlin ПРИ gremlin ТЧК ru>
GPG: 8832FE9FA791F7968AC96E4E909DAC45EF3B1FA8 @ hkp://keys.gnupg.net