7.2 - RHSA-2011:0412

Problem Description:

Updated glibc packages that fix multiple security issues are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64 Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64

3. Description:

The glibc packages contain the standard C libraries used by multiple programs on the system. These packages contain the standard C and the standard math libraries. Without these two libraries, a Linux system cannot function properly.

The fix for CVE-2010-3847 introduced a regression in the way the dynamic loader expanded the $ORIGIN dynamic string token specified in the RPATH and RUNPATH entries in the ELF library header. A local attacker could use this flaw to escalate their privileges via a setuid or setgid program using such a library. (CVE-2011-0536)

It was discovered that the glibc addmntent() function did not sanitize its input properly. A local attacker could possibly use this flaw to inject malformed lines into /etc/mtab via certain setuid mount helpers, if the attacker were allowed to mount to an arbitrary directory under their control. (CVE-2010-0296)

It was discovered that the glibc fnmatch() function did not properly restrict the use of alloca(). If the function was called on sufficiently large inputs, it could cause an application using fnmatch() to crash or, possibly, execute arbitrary code with the privileges of the application. (CVE-2011-1071)

It was discovered that the locale command did not produce properly escaped output as required by the POSIX specification. If an attacker were able to set the locale environment variables in the environment of a script that performed shell evaluation on the output of the locale command, and that script were run with different privileges than the attacker's, it could execute arbitrary code with the privileges of the script. (CVE-2011-1095)

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

4. Solution:

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

This update is available via the Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at https://access.redhat.com/kb/docs/DOC-11259

5. Bugs fixed (http://bugzilla.redhat.com/):

559579 - CVE-2010-0296 glibc: Improper encoding of names with certain special character in utilities for writing to mtab table 625893 - CVE-2011-1095 glibc: insufficient quoting in the locale command output 667974 - CVE-2011-0536 glibc: CVE-2010-3847 fix causes linker to search CWD when running privileged program with $ORIGIN in R*PATH 681054 - CVE-2011-1071 glibc: fnmatch() alloca()-based memory corruption flaw 682991 - iconv regression