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List:       oss-security
Subject:    [oss-security] Re: eCryptfs key wrapping help to crack user password
From:       cve-assign () mitre ! org
Date:       2015-02-28 4:11:46
Message-ID: 20150228041146.904966C0016 () smtpvmsrv1 ! mitre ! org
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> In this case, a wrapping key is generated from the user password
> using the hash function SHA-512 applied 65536 times. By default, the
> wrapping key is hashed with the default fixed salt
> (0x0011223344556677) and stored in the a file.
> This was already noticed in bug :
> https://bugs.launchpad.net/ecryptfs/+bug/906550


> https://bugs.launchpad.net/ecryptfs/+bug/906550/comments/5

> all installations end up wrapping (encrypting) the mount passphrase
> with the user login password and the DEFAULT SALT VALUE. A unique salt
> value among almost all installations makes them a convenient target
> for a rainbow table attack on the wrapped-passphrase file.

> I got here because I am dabbling with a config package to implement
> mandatory eCryptfs encrypted home for all users of a system

Use CVE-2014-9687. Our interpretation is that this is a vendor CVE
request based on a vendor's perspective that ecryptfs-setup-private's
use of the default salt was never the intended behavior. (For example,
http://bazaar.launchpad.net/~ecryptfs/ecryptfs/trunk/view/head:/doc/beginners_guide/ecryptfs_beginners_guide.tex
says "It is highly advised that you also provide a salt along with the
password, which will help make an attack against your files harder
than if you use the default salt.")

- -- 
CVE assignment team, MITRE CVE Numbering Authority
M/S M300
202 Burlington Road, Bedford, MA 01730 USA
[ PGP key available through http://cve.mitre.org/cve/request_id.html ]
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