RHSA-2007:0737 - Security Advisory

Topic

Updated pam packages that fix two security flaws, resolve two bugs, and
add an enhancement are now available for Red Hat Enterprise Linux 4.

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

Description

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

A flaw was found in the way pam_console set console device permissions. It
was possible for various console devices to retain ownership of the console
user after logging out, possibly leaking information to another local user.
(CVE-2007-1716)

A flaw was found in the way the PAM library wrote account names to the
audit subsystem. An attacker could inject strings containing parts of audit
messages, which could possibly mislead or confuse audit log parsing tools.
(CVE-2007-3102)

As well, these updated packages fix the following bugs:

• the pam_xauth module, which is used for copying the X11 authentication

cookie, did not reset the "XAUTHORITY" variable in certain circumstances,
causing unnecessary delays when using su command.

• when calculating password similarity, pam_cracklib disregarded changes

to the last character in passwords when "difok=x" (where "x" is the
number of characters required to change) was configured in
"/etc/pam.d/system-auth". This resulted in password changes that should
have been successful to fail with the following error:

BAD PASSWORD: is too similar to the old one

This issue has been resolved in these updated packages.

• the pam_limits module, which provides setting up system resources limits

for user sessions, reset the nice priority of the user session to "0" if it
was not configured otherwise in the "/etc/security/limits.conf"
configuration file.

These updated packages add the following enhancement:

• a new PAM module, pam_tally2, which allows accounts to be locked after a

maximum number of failed log in attempts.

All users of PAM should upgrade to these updated packages, which resolve
these issues and add this enhancement.

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 4 x86_64
• Red Hat Enterprise Linux Server 4 ia64
• Red Hat Enterprise Linux Server 4 i386
• Red Hat Enterprise Linux Workstation 4 x86_64
• Red Hat Enterprise Linux Workstation 4 ia64
• Red Hat Enterprise Linux Workstation 4 i386
• Red Hat Enterprise Linux Desktop 4 x86_64
• Red Hat Enterprise Linux Desktop 4 i386
• Red Hat Enterprise Linux for IBM z Systems 4 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390
• Red Hat Enterprise Linux for Power, big endian 4 ppc

Fixes

• BZ - 228980 - XAUTHORITY env var not reset on 'su -'
• BZ - 230823 - CVE-2007-1716 Ownership of devices not returned to root after logout from console
• BZ - 247797 - CVE-2007-3102 audit logging of failed logins
• BZ - 267201 - pam_cracklib.so disregards changes to last char when calculating similarity

CVEs

• CVE-2007-1716
• CVE-2007-3102

References

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