(Red Hat Issues Fix) PAM Lets Local Users Gain Elevated Privileges
SecurityTracker Alert ID: 1024669|
SecurityTracker URL: http://securitytracker.com/id/1024669
CVE-2010-3316, CVE-2010-3435, CVE-2010-3853
(Links to External Site)
Date: Nov 1 2010
Disclosure of system information, Disclosure of user information, Root access via local system, User access via local system|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): prior to 1.1.3|
Several vulnerabilities were reported in PAM. A local user can obtain elevated privileges on the target system. A local user can obtain limited information about files on the target system.|
The pam_xauth module does not verify the return values of the setuid() and setgid() system calls [CVE-2010-3316]. A local user can exploit this to execute the xauth command with root privileges and read an arbitrary input file.
Tim Brown reported this vulnerability.
The pam_mail module uses root privileges when accessing user files [CVE-2010-3435]. A local user can exploit this flaw to obtain limited information about files or directories that they do not have access to.
Sebastian Krahmer of the SuSE Security Team reported this vulnerability.
The pam_namespace module executes the external script 'namespace.init' with an environment inherited from an application calling PAM [CVE-2010-3853]. A local user may be able to exploit this flaw to gain elevated privileges.
Tomas Marz reported this vulnerability.
A local user can obtain limited information about files and directories on the target system.|
A local user can obtain elevated privileges on the target system.
Red Hat has issued a fix.|
The Red Hat advisory is available at:
Vendor URL: www.kernel.org/pub/linux/libs/pam/ (Links to External Site)
Access control error|
|Underlying OS: Linux (Red Hat Enterprise)|
|Underlying OS Comments: 5|
This archive entry is a follow-up to the message listed below.|
Source Message Contents
Subject: [RHSA-2010:0819-01] Moderate: pam security update|
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Red Hat Security Advisory
Synopsis: Moderate: pam security update
Advisory ID: RHSA-2010:0819-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2010-0819.html
Issue date: 2010-11-01
CVE Names: CVE-2010-3316 CVE-2010-3435 CVE-2010-3853
Updated pam packages that fix three security issues are now available for
Red Hat Enterprise Linux 5.
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.
2. Relevant releases/architectures:
RHEL Desktop Workstation (v. 5 client) - i386, x86_64
Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64
Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64
Pluggable Authentication Modules (PAM) provide a system whereby
administrators can set up authentication policies without having to
recompile programs that handle authentication.
It was discovered that the pam_namespace module executed the external
script namespace.init with an unchanged environment inherited from an
application calling PAM. In cases where such an environment was untrusted
(for example, when pam_namespace was configured for setuid applications
such as su or sudo), a local, unprivileged user could possibly use this
flaw to escalate their privileges. (CVE-2010-3853)
It was discovered that the pam_mail module used root privileges while
accessing users' files. In certain configurations, a local, unprivileged
user could use this flaw to obtain limited information about files or
directories that they do not have access to. (CVE-2010-3435)
It was discovered that the pam_xauth module did not verify the return
values of the setuid() and setgid() system calls. A local, unprivileged
user could use this flaw to execute the xauth command with root privileges
and make it read an arbitrary input file. (CVE-2010-3316)
Red Hat would like to thank Sebastian Krahmer of the SuSE Security Team for
reporting the CVE-2010-3435 issue.
All pam users should upgrade to these updated packages, which contain
backported patches to correct these issues.
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
5. Bugs fixed (http://bugzilla.redhat.com/):
637898 - CVE-2010-3316 pam: pam_xauth missing return value checks from setuid() and similar calls
641335 - CVE-2010-3435 pam: pam_env and pam_mail accessing users' file with root privileges
643043 - CVE-2010-3853 pam: pam_namespace executes namespace.init with service's environment
6. Package List:
Red Hat Enterprise Linux Desktop (v. 5 client):
RHEL Desktop Workstation (v. 5 client):
Red Hat Enterprise Linux (v. 5 server):
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
The Red Hat security contact is <email@example.com>. More contact
details at https://www.redhat.com/security/team/contact/
Copyright 2010 Red Hat, Inc.
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