RHSA-2015:1409 - Security Advisory

Topic

Updated sudo packages that fix one security issue, three bugs, and add one
enhancement are now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Moderate 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 sudo packages contain the sudo utility which allows system
administrators to provide certain users with the permission to execute
privileged commands, which are used for system management purposes, without
having to log in as root.

It was discovered that sudo did not perform any checks of the TZ
environment variable value. If sudo was configured to preserve the TZ
environment variable, a local user with privileges to execute commands via
sudo could possibly use this flaw to achieve system state changes not
permitted by the configured commands. (CVE-2014-9680)

Note: The default sudoers configuration in Red Hat Enterprise Linux removes
the TZ variable from the environment in which commands run by sudo are
executed.

This update also fixes the following bugs:

• Previously, the sudo utility child processes could sometimes become

unresponsive because they ignored the SIGPIPE signal. With this update,
SIGPIPE handler is properly restored in the function that reads passwords
from the user, and the child processes no longer ignore SIGPIPE. As a
result, sudo child processes do not hang in this situation. (BZ#1094548)

• Prior to this update, the order in which sudo rules were processed did

not honor the user-defined sudoOrder attribute. Consequently, sudo rules
were processed in an undefined order even when the user defined the order
in sudoOrder. The implementation of SSSD support in sudo has been modified
to sort the rules according to the sudoOrder value, and sudo rules are now
sorted in the order defined by the user in sudoOrder. (BZ#1138581)

• Previously, sudo became unresponsive after the user issued a command when

a sudoers source was mentioned multiple times in the /etc/nsswitch.conf
file. The problem occurred when nsswitch.conf contained, for example, the
"sudoers: files sss sss" entry. The sudoers source processing code has been
fixed to correctly handle multiple instances of the same sudoers source.
As a result, sudo no longer hangs when a sudoers source is mentioned
multiple times in /etc/nsswitch.conf. (BZ#1147498)

In addition, this update adds the following enhancement:

• The sudo utility now supports I/O logs compressed using the zlib library.

With this update, sudo can generate zlib compressed I/O logs and also
process zlib compressed I/O logs generated by other versions of sudo with
zlib support. (BZ#1106433)

All sudo users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add this
enhancement.

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 1138267 - sudoers.ldap man page has typos in description
• BZ - 1138581 - sudo with sssd doesn't work correctly with sudoOrder option
• BZ - 1142122 - sudo option mail_no_user doesn't work
• BZ - 1144448 - sudo with ldap doesn't work correctly with 'listpw=all' and 'verifypw=all' in sudoOption entry
• BZ - 1147498 - duplicate sss module in nsswitch breaks sudo
• BZ - 1191144 - CVE-2014-9680 sudo: unsafe handling of TZ environment variable

CVEs

• CVE-2014-9680

References

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