(RHSA-2010:0819) Moderate: pam security update

Pluggable Authentication Modules (PAM) provide a system whereby
administrators can set up authentication policies without having to
recompile programs that handle authentication.

It was discovered that the pam_namespace module executed the external
script namespace.init with an unchanged environment inherited from an
application calling PAM. In cases where such an environment was untrusted
(for example, when pam_namespace was configured for setuid applications
such as su or sudo), a local, unprivileged user could possibly use this
flaw to escalate their privileges. (CVE-2010-3853)

It was discovered that the pam_mail module used root privileges while
accessing users’ files. In certain configurations, a local, unprivileged
user could use this flaw to obtain limited information about files or
directories that they do not have access to. (CVE-2010-3435)

It was discovered that the pam_xauth module did not verify the return
values of the setuid() and setgid() system calls. A local, unprivileged
user could use this flaw to execute the xauth command with root privileges
and make it read an arbitrary input file. (CVE-2010-3316)

Red Hat would like to thank Sebastian Krahmer of the SuSE Security Team for
reporting the CVE-2010-3435 issue.

All pam users should upgrade to these updated packages, which contain
backported patches to correct these issues.