SUSE-SA:2003:040: sendmail, sendmail-tls
Critical Nessus Plugin ID 13808
SynopsisThe remote host is missing a vendor-supplied security patch
DescriptionThe remote host is missing the patch for the advisory SUSE-SA:2003:040 (sendmail, sendmail-tls).
sendmail is the most widely used mail transport agent (MTA) in the internet. A remotely exploitable buffer overflow has been found in all versions of sendmail that come with SUSE products. These versions include sendmail-8.11 and sendmail-8.12 releases. sendmail is the MTA subsystem that is installed by default on all SUSE products up to and including SUSE LINUX 8.0 and the SUSE LINUX Enterprise Server 7.
The vulnerability discovered is known as the prescan()-bug and is not related to the vulnerability found and fixed in April 2003. The error in the code can cause heap or stack memory to be overwritten, triggered by (but not limited to) functions that parse header addresses.
There is no known workaround for this vulnerability other than using a different MTA. The vulnerability is triggered by an email message sent through the sendmail MTA subsystem. In that respect, it is different from commonly known bugs that occur in the context of an open TCP connection. By consequence, the vulnerability also exists if email messages get forwarded over a relay that itself does not run a vulnerable MTA. This specific detail and the wide distribution of sendmail in the internet causes this vulnerability to be considered a flaw of major severity. We recommend to install the update packages that are provided for download at the locations listed below.
We thank Michal Zalewski who discovered this vulnerability and the friendly people from Sendmail Inc (Claus Assmann) who have communicated problem to SUSE Security.
Please download the update package for your distribution and verify its integrity by the methods listed in section 3) of this announcement.
Then, install the package using the command 'rpm -Fhv file.rpm' to apply the update.