5 - USN-612-5

A security issue affects the following Ubuntu releases:

Ubuntu 7.04 Ubuntu 7.10 Ubuntu 8.04 LTS

This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.

The problem can be corrected by upgrading your system to the following package versions:

Ubuntu 7.04:
openssh-client 1:4.3p2-8ubuntu1.4
openssh-client-udeb 1:4.3p2-8ubuntu1.4

Ubuntu 7.10:
openssh-client 1:4.6p1-5ubuntu0.5
openssh-client-udeb 1:4.6p1-5ubuntu0.5

Ubuntu 8.04 LTS:
openssh-client 1:4.7p1-8ubuntu1.2
openssh-client-udeb 1:4.7p1-8ubuntu1.2

After performing a standard system upgrade, users are encouraged to re-run ssh-vulnkey on their systems.

Details follow:

Matt Zimmerman discovered that entries in ~/.ssh/authorized_keys with options (such as "no-port-forwarding" or forced commands) were ignored by the new ssh-vulnkey tool introduced in OpenSSH (see USN-612-2). This could cause some compromised keys not to be listed in ssh-vulnkey's output.

This update also adds more information to ssh-vulnkey's manual page.

Original advisory details:

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, OpenVPN
and SSL certificates.