Medium Nessus Plugin ID 13783
SynopsisThe remote host is missing a vendor-supplied security patch
DescriptionThe remote host is missing the patch for the advisory SUSE-SA:2003:011 (openssl).
OpenSSL is an implementation of the Secure Sockets Layer and Transport Layer Security protocols and provides strong cryptography for many applications in a Linux system. It is a default package in all SUSE products.
A security weakness has been found, known as 'Vaudenay timing attack on CBC', named after one of the discoverers (Brice Canvel (EPFL), Alain Hiltgen (UBS), Serge Vaudenay (EPFL), and Martin Vuagnoux (EPFL, Ilion)).
The weakness may allow an attacker to obtain a plaintext data block by observing timing differences in response to two different error cases (cipher padding errors vs. MAC verification errors).
In order to exploit this vulnerability, the attacker has to meet certain requirements: The network connection between client and server must be of high quality to be able to observe timing differences, the attacker must be able to perform a man-in-the-middle attack, the transactions must repeatedly contain the same (encrypted) plain text block (such as a pop password or alike), and decoding failures in the SSL layer must not be propagated to the application that is using the SSL connection.
These exploitation conditions considerably reduce the security risk imposed by the vulnerability. However, we recommend to completely remedy this weakness by installing the update packages for your system according to the following guidelines. There does not exist any temporary workaround for this problem other than applying the update packages.
Please download the update package for your distribution and verify its integrity by the methods listed in section 3) of this announcement.