RHSA-2011:0261 - Security Advisory

Topic

Updated bash packages that fix one security issue and several bugs are now
available for Red Hat Enterprise Linux 4.

The Red Hat Security Response Team has rated this update as having low
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

Description

Bash (Bourne-again shell) is the default shell for Red Hat Enterprise
Linux.

It was found that certain scripts bundled with the Bash documentation
created temporary files in an insecure way. A malicious, local user could
use this flaw to conduct a symbolic link attack, allowing them to overwrite
the contents of arbitrary files accessible to the victim running the
scripts. (CVE-2008-5374)

This update also fixes the following bugs:

• If a child process's PID was the same as the PID of a previously ended

child process, Bash did not wait for that child process. In some cases this
caused "Resource temporarily unavailable" errors. With this update, Bash
recycles PIDs and waits for processes with recycled PIDs. (BZ#521134)

• Bash's built-in "read" command had a memory leak when "read" failed due

to no input (pipe for stdin). With this update, the memory is correctly
freed. (BZ#537029)

• Bash did not correctly check for a valid multi-byte string when setting

the IFS value, causing Bash to crash. With this update, Bash checks the
multi-byte string and no longer crashes. (BZ#539536)

• Bash incorrectly set locale settings when using the built-in "export"

command and setting the locale on the same line (for example, with
"LC_ALL=C export LC_ALL"). With this update, Bash correctly sets locale
settings. (BZ#539538)

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

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
http://kbase.redhat.com/faq/docs/DOC-11259

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 - 475474 - CVE-2008-5374 bash: Insecure temporary file use in aliasconv.sh, aliasconv.bash, cshtobash (symlink attack)
• BZ - 521134 - Bash doesn't wait for backgrounded process if its PID is recycled

CVEs

• CVE-2008-5374

References

• https://access.redhat.com/security/updates/classification/#low