The remote host is missing an update to krb5 announced via advisory USN-755-1.

The problem can be corrected by upgrading your system to the following package versions: Ubuntu 6.06 LTS: libkadm55 1.4.3-5ubuntu0.8 libkrb53 1.4.3-5ubuntu0.8 Ubuntu 7.10: libkadm55 1.6.dfsg.1-7ubuntu0.2 libkrb53 1.6.dfsg.1-7ubuntu0.2 Ubuntu 8.04 LTS: libkadm55 1.6.dfsg.3~beta1-2ubuntu1.1 libkrb53 1.6.dfsg.3~beta1-2ubuntu1.1 Ubuntu 8.10: libkadm55 1.6.dfsg.4~beta1-3ubuntu0.1 libkrb53 1.6.dfsg.4~beta1-3ubuntu0.1 After a standard system upgrade you need to restart any services using the Kerberos libraries to effect the necessary changes. https://secure1.securityspace.com/smysecure/catid.html?in=USN-755-1

Multiple flaws were discovered in the Kerberos GSS-API and ASN.1 routines that did not correctly handle certain requests. An unauthenticated remote attacker could send specially crafted traffic to crash services using the Kerberos library, leading to a denial of service.