RHSA-2015:2019 - Security Advisory

Topic

Updated sssd packages that fix one security issue and several bugs are now
available for Red Hat Enterprise Linux 6.

Red Hat Product Security 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

The System Security Services Daemon (SSSD) service provides a set of
daemons to manage access to remote directories and authentication
mechanisms. It also provides the Name Service Switch (NSS) and the
Pluggable Authentication Modules (PAM) interfaces toward the system, and a
pluggable back-end system to connect to multiple different account sources.

It was found that SSSD's Privilege Attribute Certificate (PAC) responder
plug-in would leak a small amount of memory on each authentication request.
A remote attacker could potentially use this flaw to exhaust all available
memory on the system by making repeated requests to a Kerberized daemon
application configured to authenticate using the PAC responder plug-in.
(CVE-2015-5292)

This update also fixes the following bugs:

• Previously, SSSD did not correctly handle sudo rules that applied to

groups with names containing special characters, such as the "(" opening
parenthesis sign. Consequently, SSSD skipped such sudo rules. The internal
sysdb search has been modified to escape special characters when searching
for objects to which sudo rules apply. As a result, SSSD applies the
described sudo rules as expected. (BZ#1258398)

• Prior to this update, SSSD did not correctly handle group names

containing special Lightweight Directory Access Protocol (LDAP) characters,
such as the "(" or ")" parenthesis signs. When a group name contained one
or more such characters, the internal cache cleanup operation failed with
an I/O error. With this update, LDAP special characters in the
Distinguished Name (DN) of a cache entry are escaped before the cleanup
operation starts. As a result, the cleanup operation completes successfully
in the described situation. (BZ#1264098)

• Applications performing Kerberos authentication previously increased the

memory footprint of the Kerberos plug-in that parses the Privilege
Attribute Certificate (PAC) information. The plug-in has been updated to
free the memory it allocates, thus fixing this bug. (BZ#1268783)

• Previously, when malformed POSIX attributes were defined in an Active

Directory (AD) LDAP server, SSSD unexpectedly switched to offline mode.
This update relaxes certain checks for AD POSIX attribute validity. As a
result, SSSD now works as expected even when malformed POSIX attributes are
present in AD and no longer enters offline mode in the described situation.
(BZ#1268784)

All sssd users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing the
update, the sssd service will be restarted automatically. Additionally, all
running applications using the PAC responder plug-in must be restarted for
the changes to take effect.

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 for x86_64 - Extended Update Support 6.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.7 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.7 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.7 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 i386
• Red Hat Enterprise Linux for SAP Solutions for x86_64 - Extended Update Support 6.7 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.7 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.7 i386
• Red Hat Enterprise Linux EUS Compute Node 6.7 x86_64
• 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 - 1267580 - CVE-2015-5292 sssd: memory leak in the sssd_pac_plugin
• BZ - 1268783 - Memory leak / possible DoS with krb auth. [rhel 6.7.z]

CVEs

• CVE-2015-5292

References

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