RHEL 6 / 7 : pam (RHSA-2015:1640)
Medium Nessus Plugin ID 85530
SynopsisThe remote Red Hat host is missing one or more security updates.
DescriptionAn updated pam package that fixes one security issue is now available for Red Hat Enterprise Linux 6 and 7.
Red Hat Product Security has rated this update as having Moderate 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.
Pluggable Authentication Modules (PAM) provide a system whereby administrators can set up authentication policies without having to recompile programs to handle authentication.
It was discovered that the _unix_run_helper_binary() function of PAM's unix_pam module could write to a blocking pipe, possibly causing the function to become unresponsive. An attacker able to supply large passwords to the unix_pam module could use this flaw to enumerate valid user accounts, or cause a denial of service on the system.
Red Hat would like to thank Sebastien Macke of Trustwave SpiderLabs for reporting this issue.
All pam users are advised to upgrade to this updated package, which contains a backported patch to correct this issue.
SolutionUpdate the affected pam, pam-debuginfo and / or pam-devel packages.