as31 2.3.1-4 does not seed the random number generator and generates predictable temporary file names, which makes it easier for local users to create or truncate files via a symlink attack.
http://www.openwall.com/lists/oss-security/2012/08/31/9
http://www.openwall.com/lists/oss-security/2012/07/06/3
http://www.openwall.com/lists/oss-security/2012/07/05/1
http://www.openwall.com/lists/oss-security/2012/01/24/7