USN-1237-1: PAM vulnerabilities

Releases

• Ubuntu 11.10
• Ubuntu 11.04
• Ubuntu 10.10
• Ubuntu 10.04
• Ubuntu 8.04

Packages

• pam - Pluggable Authentication Modules

Details

Kees Cook discovered that the PAM pam_env module incorrectly handled
certain malformed environment files. A local attacker could use this flaw
to cause a denial of service, or possibly gain privileges. The default
compiler options for affected releases should reduce the vulnerability to a
denial of service. (CVE-2011-3148)

Kees Cook discovered that the PAM pam_env module incorrectly handled
variable expansion. A local attacker could use this flaw to cause a denial
of service. (CVE-2011-3149)

Stephane Chazelas discovered that the PAM pam_motd module incorrectly
cleaned the environment during execution of the motd scripts. In certain
environments, a local attacker could use this to execute arbitrary code
as root, and gain privileges.

Update instructions

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

Ubuntu 8.04

• libpam-modules - 0.99.7.1-5ubuntu6.5

Ubuntu 11.10

• libpam-modules - 1.1.3-2ubuntu2.1

Ubuntu 11.04

• libpam-modules - 1.1.2-2ubuntu8.4

Ubuntu 10.10

• libpam-modules - 1.1.1-4ubuntu2.4

Ubuntu 10.04

• libpam-modules - 1.1.1-2ubuntu5.4

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

References

• CVE-2011-3149
• CVE-2011-3148
• CVE-2011-3628