Ubuntu 4.10 / 5.04 : openssl weak default configuration (USN-179-1)

Ubuntu Security Notice (C) 2005-2013 Canonical, Inc. / NASL script (C) 2006-2013 Tenable Network Security, Inc.


Synopsis :

The remote Ubuntu host is missing one or more security-related patches.

Description :

The current default algorithm for creating 'message digests'
(electronic signatures) for certificates created by openssl is MD5.
However, this algorithm is not deemed secure any more, and some
practical attacks have been demonstrated which could allow an attacker
to forge certificates with a valid certification authority signature
even if he does not know the secret CA signing key.

Therefore all Ubuntu versions of openssl have now been changed to use
SHA-1 by default. This is a more appropriate default algorithm for the
majority of use cases
however, if you still want to use MD5 as
default, you can revert this change by changing the two instances of
'default_md = sha1' to 'default_md = md5' in /etc/ssl/openssl.cnf.

A detailed explanation and further links can be found at

http://www.cits.rub.de/MD5Collisions/

Solution :

Update the affected libssl-dev, libssl0.9.7 and / or openssl packages.

Risk factor :

Medium / CVSS Base Score : 5.0
(CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N)

Family: Ubuntu Local Security Checks

Nessus Plugin ID: 20589 ()

Bugtraq ID:

CVE ID: CVE-2005-2946