RHSA-2014:1312 - Security Advisory

Topic

[Updated September 30, 2014]
This advisory has been updated with information on restarting system
services after applying this update. No changes have been made to the
original packages.

Updated bash Shift_JIS packages that fix one security issue are now
available for Red Hat Enterprise Linux 5 and 6.

Red Hat Product Security has rated this update as having Important 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

The GNU Bourne Again shell (Bash) is a shell and command language
interpreter compatible with the Bourne shell (sh). Bash is the default
shell for Red Hat Enterprise Linux.

Shift_JIS, also known as "SJIS", is a character encoding for the Japanese
language. This package provides bash support for the Shift_JIS encoding.

It was found that the fix for CVE-2014-6271 was incomplete, and Bash still
allowed certain characters to be injected into other environments via
specially crafted environment variables. An attacker could potentially use
this flaw to override or bypass environment restrictions to execute shell
commands. Certain services and applications allow remote unauthenticated
attackers to provide environment variables, allowing them to exploit this
issue. (CVE-2014-7169)

Applications which directly create bash functions as environment variables
need to be made aware of changes to the way names are handled by this
update. Note that certain services, screen sessions, and tmux sessions may
need to be restarted, and affected interactive users may need to re-login.
Installing these updated packages without restarting services will address
the vulnerability, but functionality may be impacted until affected
services are restarted. For more information see the Knowledgebase article
at https://access.redhat.com/articles/1200223

Note: Docker users are advised to use "yum update" within their containers,
and to commit the resulting changes.

For additional information on CVE-2014-6271 and CVE-2014-7169, refer to the
aforementioned Knowledgebase article.

All users who require Shift_JIS encoding support with Bash built-in
functions are advised to upgrade to these updated packages, which contain a
backported patch to correct this issue.

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/articles/11258

Affected Products

• Red Hat S-JIS Support (for RHEL Server) 6 x86_64
• Red Hat S-JIS Support (for RHEL Server) 6 i386
• Red Hat S-JIS Support (for RHEL Server) 5 x86_64
• Red Hat S-JIS Support (for RHEL Server) 5 ia64
• Red Hat S-JIS Support (for RHEL Server) 5 i386

Fixes

• BZ - 1146319 - CVE-2014-7169 bash: code execution via specially-crafted environment (Incomplete fix for CVE-2014-6271)

CVEs

• CVE-2014-7169
• CVE-2014-7186
• CVE-2014-7187

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/articles/1200223