RHSA-2008:0907 - Security Advisory

Topic

An updated pam_krb5 package that fixes a security issue is now available
for Red Hat Enterprise Linux 5.

This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

Description

The pam_krb5 module allows Pluggable Authentication Modules (PAM) aware
applications to use Kerberos to verify user identities by obtaining user
credentials at log in time.

A flaw was found in the pam_krb5 "existing_ticket" configuration option. If
a system is configured to use an existing credential cache via the
"existing_ticket" option, it may be possible for a local user to gain
elevated privileges by using a different, local user's credential cache.
(CVE-2008-3825)

Red Hat would like to thank Stephane Bertin for responsibly disclosing this
issue.

Users of pam_krb5 should upgrade to this updated package, which contains a
backported patch to resolve this issue.

Solution

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/FAQ_58_10188

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.2 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.2 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.2 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.2 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 461960 - CVE-2008-3825 pam_krb5 existing_ticket permission flaw

CVEs

• CVE-2008-3825

References

• http://www.redhat.com/security/updates/classification/#moderate