The remote host is missing an update to python-crypto announced via advisory USN-729-1.

The problem can be corrected by upgrading your system to the following package versions: Ubuntu 6.06 LTS: python2.4-crypto 2.0.1+dfsg1-1ubuntu1.1 Ubuntu 7.10: python-crypto 2.0.1+dfsg1-2ubuntu1.1 Ubuntu 8.04 LTS: python-crypto 2.0.1+dfsg1-2.1ubuntu1.1 Ubuntu 8.10: python-crypto 2.0.1+dfsg1-2.3ubuntu0.1 In general, a standard system upgrade is sufficient to effect the necessary changes. https://secure1.securityspace.com/smysecure/catid.html?in=USN-729-1

Mike Wiacek discovered that the ARC2 implementation in Python Crypto did not correctly check the key length. If a user or automated system were tricked into processing a malicious ARC2 stream, a remote attacker could execute arbitrary code or crash the application using Python Crypto, leading to a denial of service.