RHSA-2011:0153

Problem Description:

Updated exim packages that fix one security issue are now available for Red
Hat Enterprise Linux 4 and 5.

The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64
Red Hat Enterprise Linux AS version 4 - i386, ia64, ppc, s390, s390x, x86_64
Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64
Red Hat Enterprise Linux Desktop version 4 - i386, x86_64
Red Hat Enterprise Linux ES version 4 - i386, ia64, x86_64
Red Hat Enterprise Linux WS version 4 - i386, ia64, x86_64

3. Description:

Exim is a mail transport agent (MTA) developed at the University of
Cambridge for use on UNIX systems connected to the Internet.

A privilege escalation flaw was discovered in Exim. If an attacker were
able to gain access to the "exim" user, they could cause Exim to execute
arbitrary commands as the root user. (CVE-2010-4345)

This update adds a new configuration file, "/etc/exim/trusted-configs". To
prevent Exim from running arbitrary commands as root, Exim will now drop
privileges when run with a configuration file not listed as trusted. This
could break backwards compatibility with some Exim configurations, as the
trusted-configs file only trusts "/etc/exim/exim.conf" and
"/etc/exim/exim4.conf" by default. If you are using a configuration file
not listed in the new trusted-configs file, you will need to add it
manually.

Additionally, Exim will no longer allow a user to execute exim as root with
the -D command line option to override macro definitions. All macro
definitions that require root permissions must now reside in a trusted
configuration file.

Users of Exim are advised to upgrade to these updated packages, which
contain a backported patch to correct this issue. After installing this
update, the exim daemon will be restarted automatically.

4. Solution:

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

5. Bugs fixed (http://bugzilla.redhat.com/):

662012 - CVE-2010-4345 exim privilege escalation