Moderate: pam security, bug fix, and enhancement update
Security Advisory: Moderate
Updated pam packages that fix two security issues, several bugs, and add
various enhancements 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.
Pluggable Authentication Modules (PAM) provide a system whereby
administrators can set up authentication policies without having to
recompile programs to handle authentication.
A stack-based buffer overflow flaw was found in the way the pam_env module
parsed users' "~/.pam_environment" files. If an application's PAM
configuration contained "user_readenv=1" (this is not the default), a
local attacker could use this flaw to crash the application or, possibly,
escalate their privileges. (CVE-2011-3148)
A denial of service flaw was found in the way the pam_env module expanded
certain environment variables. If an application's PAM configuration
contained "user_readenv=1" (this is not the default), a local attacker
could use this flaw to cause the application to enter an infinite loop.
(CVE-2011-3149)
Red Hat would like to thank Kees Cook of the Google ChromeOS Team for
reporting the CVE-2011-3148 and CVE-2011-3149 issues.
These updated pam packages include numerous bug fixes and enhancements.
Space precludes documenting all of these changes in this advisory. Users
are directed to the Red Hat Enterprise Linux 6.4 Technical Notes, linked
to in the References, for information on the most significant of these
changes.
All pam users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add these
enhancements.
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/knowledge/articles/11258
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