exim security update

CentOS Errata and Security Advisory CESA-2011:0153

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.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2011-April/079500.html
https://lists.centos.org/pipermail/centos-announce/2011-April/079501.html
https://lists.centos.org/pipermail/centos-announce/2011-January/079405.html
https://lists.centos.org/pipermail/centos-announce/2011-January/079406.html

Affected packages:
exim
exim-doc
exim-mon
exim-sa

Upstream details at:
https://access.redhat.com/errata/RHSA-2011:0153