A weakness has been discovered in the random number generator used by OpenSSL on Debian and Ubuntu systems. As a result of this weakness, certain encryption keys are much more common than they should be, such that an attacker could guess the key through a brute-force attack given minimal knowledge of the system.
This particularly affects the use of encryption keys in OpenSSH. This vulnerability only affects operating systems which (like Ubuntu) are based on Debian. However, other systems can be indirectly affected if weak keys are imported into them.
We consider this an extremely serious vulnerability, and urge all users to act immediately to secure their systems. The following Ubuntu releases are affected: Ubuntu 7.04 Ubuntu 7.10 Ubuntu 8.04 LTS
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
ISOs available already on ubuntu.com and mirrors will not be updated with the new packages, but using the Update Manager to get security updates will replace the impacted packages. Users should then regenerate new keys.
ShipIt has stopped mailing CDs.
The 8.04.1 point release, expected in July, will include the updated packages.
Please see usn-612-2 for the latest information regarding updating your system and taking appropriate protective measures.