1.189.1. RHSA-2010:0891: Moderate security update
Updated pam packages that fix three security issues 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 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_env and pam_mail modules used root privileges while accessing user's files. A local, unprivileged user could use this flaw to obtain information, from the lines that have the KEY=VALUE format expected by pam_env, from an arbitrary file. Also, in certain configurations, a local, unprivileged user using a service for which the pam_mail module was configured for, could use this flaw to obtain limited information about files or directories that they do not have access to. (CVE-2010-3435)
Note: As part of the fix for CVE-2010-3435, this update changes the default value of pam_env's configuration option user_readenv to 0, causing the module to not read user's ~/.pam_environment configuration file by default, as reading it may introduce unexpected changes to the environment of the service using PAM, or PAM modules consulted after pam_env.
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.
1.189.2. RHBA-2011:0685: bug fix and enhancement update
Updated pam packages that fix bugs and add enhancements are now available.
Pluggable Authentication Modules (PAM) provide a system whereby administrators can set up authentication policies without having to recompile programs to handle authentication.
These updated pam packages fix the following bugs:
When the pam packages were updated, the /var/log/tallylog and /var/log/faillog files were overwritten with empty files because of an incorrect condition check in the %post script. This has been corrected, and PAM no longer attempts to overwrite tallylog and faillog files when they exist prior to update. (
BZ#614766)
A code review revealed several small memory leaks and improperly handled error paths in pam_namespace, pam_selinux, pam_limits, pam_pwhistory, pam_time, and pam_group modules. These issues have been corrected. (
BZ#679069)
These updated packages also provide the following enhancements:
The pam_limits module, which sets resource limits for processes, now supports matching individual and ranges of user and group identifiers in its limits.conf configuration file. (
BZ#622847)
A new pam_faillock module was added to support temporary locking of user accounts in the event of multiple failed authentication attempts. This new module improves functionality over the existing pam_tally2 module, as it also allows temporary locking when the authentication attempts are done over a screen saver. (
BZ#644971)
The audit records provided by the pam_selinux and pam_tally2 modules have been improved to include tty and remote hostname information in each recorded event. (
BZ#677664)
All pam users are advised to upgrade to these updated packages, which resolve these issues and add these enhancements.
