RHSA-2011:0840 - Security Advisory

Topic

Updated dhcp packages that fix one security issue are now available for
Red Hat Enterprise Linux 3 Extended Life Cycle Support.

The Red Hat Security Response Team has rated this update as having
important 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.

Description

The Dynamic Host Configuration Protocol (DHCP) is a protocol that allows
individual devices on an IP network to get their own network configuration
information, including an IP address, a subnet mask, and a broadcast
address.

It was discovered that the DHCP client daemon, dhclient, did not
sufficiently sanitize certain options provided in DHCP server replies, such
as the client hostname. A malicious DHCP server could send such an option
with a specially-crafted value to a DHCP client. If this option's value was
saved on the client system, and then later insecurely evaluated by a
process that assumes the option is trusted, it could lead to arbitrary code
execution with the privileges of that process. (CVE-2011-0997)

Red Hat would like to thank Sebastian Krahmer of the SuSE Security Team for
reporting this issue.

All dhclient users should upgrade to these updated packages, which contain
a backported patch to correct this issue.

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
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server - Extended Life Cycle Support 3 i386

Fixes

• BZ - 689832 - CVE-2011-0997 dhclient: insufficient sanitization of certain DHCP response values

CVEs

• CVE-2011-0997

References

• https://access.redhat.com/security/updates/classification/#important