Somebody backdoored the source code for Sendmail on the official server.
So if you recompile from scratch, your sendmail is 0wned.
Another reason not to run mail systems as root
http://rss.com.com/2100-1001-961311.html?type=ptpart=rsstag=feedsubj=news
By Robert Lemos
Staff Writer, CNET News.com
October 8, 2002, 5:57 PM PT
Some copies of a popular mail-server program are implanted with a back door
that could allow access to Internet attackers, security experts warned Tuesday.
A Computer Emergency Response Team (CERT) Coordination Center advisory said
that illicit code added to the Sendmail package creates a back door when
the program is compiled from its source code. Such a compromised
program--called a Trojan horse by security experts--can leave networks
exposed to attack and administrators unaware of the vulnerabilities.
The source code files of Sendmail 8.12.6 were apparently modified as far
back as Sept. 28, according to the advisory. The Sendmail Consortium
http://www.sendmail.org removed file transfer protocol (FTP) access to the
server on Sunday. A safe version of the file can still be downloaded via
the Web.
If you download the Sendmail distribution you MUST verify the PGP
signature, stated the consortium on its site. Do NOT use Sendmail without
verifying the integrity of the source code.
The added code links to a specific server on the Internet, said CERT in its
advisory. The security group also recommends that anyone who downloads
Sendmail verify the file's integrity.
Because only the act of compiling the file activates the hostile program
code, restarting the Sendmail server seems to deactivate the backdoor