oss-sec mailing list archives

Re: kwallet crypto misuse


From: Daniel Kahn Gillmor <dkg () fifthhorseman net>
Date: Fri, 03 Jan 2014 12:44:42 -0500

On 01/03/2014 02:27 AM, gremlin () gremlin ru wrote:
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.

what kind of hashing and salting are you talking about?  i don't think
hashing and salting makes sense in the context that you were quoting
above.  Are you aware that kwallet stores a database of passwords that
need to be able to be produced back for the user (or the user's
applications) in the clear?

        --dkg

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