RHSA-2011:1221 - Security Advisory

Topic

Updated samba and cifs-utils packages that fix multiple security issues and
one bug are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
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.

Description

Samba is a suite of programs used by machines to share files, printers, and
other information. The cifs-utils package contains utilities for mounting
and managing CIFS (Common Internet File System) shares.

A cross-site scripting (XSS) flaw was found in the password change page of
the Samba Web Administration Tool (SWAT). If a remote attacker could trick
a user, who was logged into the SWAT interface, into visiting a
specially-crafted URL, it would lead to arbitrary web script execution in
the context of the user's SWAT session. (CVE-2011-2694)

It was found that SWAT web pages did not protect against Cross-Site
Request Forgery (CSRF) attacks. If a remote attacker could trick a user,
who was logged into the SWAT interface, into visiting a specially-crafted
URL, the attacker could perform Samba configuration changes with the
privileges of the logged in user. (CVE-2011-2522)

It was found that the fix for CVE-2010-0547, provided in the cifs-utils
package included in the GA release of Red Hat Enterprise Linux 6, was
incomplete. The mount.cifs tool did not properly handle share or directory
names containing a newline character, allowing a local attacker to corrupt
the mtab (mounted file systems table) file via a specially-crafted CIFS
share mount request, if mount.cifs had the setuid bit set. (CVE-2011-2724)

It was found that the mount.cifs tool did not handle certain errors
correctly when updating the mtab file. If mount.cifs had the setuid bit
set, a local attacker could corrupt the mtab file by setting a small file
size limit before running mount.cifs. (CVE-2011-1678)

Note: mount.cifs from the cifs-utils package distributed by Red Hat does
not have the setuid bit set. We recommend that administrators do not
manually set the setuid bit for mount.cifs.

Red Hat would like to thank the Samba project for reporting CVE-2011-2694
and CVE-2011-2522, and Dan Rosenberg for reporting CVE-2011-1678. Upstream
acknowledges Nobuhiro Tsuji of NTT DATA Security Corporation as the
original reporter of CVE-2011-2694, and Yoshihiro Ishikawa of LAC Co., Ltd.
as the original reporter of CVE-2011-2522.

This update also fixes the following bug:

• If plain text passwords were used ("encrypt passwords = no" in

"/etc/samba/smb.conf"), Samba clients running the Windows XP or Windows
Server 2003 operating system may not have been able to access Samba shares
after installing the Microsoft Security Bulletin MS11-043. This update
corrects this issue, allowing such clients to use plain text passwords to
access Samba shares. (BZ#728517)

Users of samba and cifs-utils are advised to upgrade to these updated
packages, which contain backported patches to resolve these issues. After
installing this update, the smb service will be restarted automatically.

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

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 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 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 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 6.1 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 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 (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 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 - 695925 - CVE-2011-1678 samba/cifs-utils: mount.cifs and umount.cifs fail to anticipate RLIMIT_FSIZE
• BZ - 721348 - CVE-2011-2522 samba (SWAT): Absent CSRF protection in various Samba web configuration formulars
• BZ - 722537 - CVE-2011-2694 samba (SWAT): XSS flaw in Change Password page
• BZ - 726691 - CVE-2011-2724 samba, cifs-utils: mount.cifs incorrect fix for CVE-2010-0547
• BZ - 728517 - Windows security patch KB2536276 prevents access to samba shares

CVEs

• CVE-2011-2522
• CVE-2011-2694
• CVE-2011-1678
• CVE-2011-2724
• CVE-2011-3585

References

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