Summary:

An attacker could cause PAM to read or delete arbitrary files or cause it
to crash.

Software Description:
- pam: Pluggable Authentication Modules

Details:

Marcus Granado discovered that PAM incorrectly handled configuration files
with non-ASCII usernames. A remote attacker could use this flaw to cause a
denial of service, or possibly obtain login access with a different users
username. This issue only affected Ubuntu 8.04 LTS. (CVE-2009-0887)

It was discovered that the PAM pam_xauth, pam_env and pam_mail modules
incorrectly handled dropping privileges when performing operations. A local
attacker could use this flaw to read certain arbitrary files, and access
other sensitive information. (CVE-2010-3316, CVE-2010-3430, CVE-2010-3431,
CVE-2010-3435)

It was discovered that the PAM pam_namespace module incorrectly cleaned the
environment during execution of the namespace.init script. A local attacker
could use this flaw to possibly gain privileges. (CVE-2010-3853)

It was discovered that the PAM pam_xauth module incorrectly handled certain
failures. A local attacker could use this flaw to delete certain unintended
files. (CVE-2010-4706)

It was discovered that the PAM pam_xauth module incorrectly verified
certain file properties. A local attacker could use this flaw to cause a
denial of service. (CVE-2010-4707)

Update instructions:

The problem can be corrected by updating your system.