Ubuntu Security Notice USN-1108-2

19th April, 2011

dhcp3 vulnerability

A security issue affects these releases of Ubuntu and its
derivatives:

• Ubuntu 10.10



• Ubuntu 10.04 LTS



• Ubuntu 9.10

Summary

An attacker's DHCP server could send crafted responses to your computer and
cause it to run programs as root.

Software description

• dhcp3
  - DHCP Client
  
  

Details

USN-1108-1 fixed vulnerabilities in DHCP. Due to an error, the patch to fix
the vulnerability was not properly applied on Ubuntu 9.10 and higher. This
update fixes the problem.

Original advisory details:

Sebastian Krahmer discovered that the dhclient utility incorrectly filtered
crafted responses. An attacker could use this flaw with a malicious DHCP
server to execute arbitrary code, resulting in root privilege escalation.

Update instructions

The problem can be corrected by updating your system to the following
package version:

Ubuntu 10.10:

dhcp3-client

3.1.3-2ubuntu6.2

Ubuntu 10.04 LTS:

dhcp3-client

3.1.3-2ubuntu3.2

Ubuntu 9.10:

dhcp3-client

3.1.2-1ubuntu7.3

In general, a standard system update will make all the necessary changes.

References

CVE-2011-0997