(RHSA-2002:259) sendmail security update

SMRSH (the SendMail Restricted SHell) is a /bin/sh replacement for
Sendmail. It provides the ability to limit the set of executable programs
available to Sendmail.

A bug in the version of smrsh packaged as part of Sendmail 8.12.6 and
8.11.6 allows attackers to bypass shrsh’s intended restrictions. This
can be done by inserting additional commands after “||” or “/” characters,
which are not properly filtered or verified. A sucessful attack would
allow an attacker who has a local account on a system to execute arbitrary
binaries as themselves by utilizing their .forward file.

Because sendmail as shipped with Red Hat Linux Advanced Server is not
configured to use smrsh, this issue only affects users who have customized
their sendmail configuration to use smrsh.

Users who have configured sendmail to use smrsh should update to these
errata packages which contain a backported security fix, and are therefore
not vulnerable to this issue.