The System Security Services Daemon provides a set of daemons to manage access to remote directories and authentication mechanisms. It provides an NSS and PAM interface toward the system and a pluggable back-end system to connect to multiple different account sources. It is also the basis to provide client auditing and policy services for projects such as FreeIPA. A flaw was found in the SSSD PAM responder that could allow a local attacker to force SSSD to enter an infinite loop via a carefully-crafted packet. With SSSD unresponsive, legitimate users could be denied the ability to log in to the system. Red Hat would like to thank Sebastian Krahmer for reporting this issue. These updated sssd packages include a number of bug fixes and enhancements. Space precludes documenting all of these changes in this advisory. Refer to the Red Hat Enterprise Linux 5.7 Technical Notes for information about these changes: https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.7_Tech nical_Notes/sssd.html#RHSA-2011-0975 All sssd users are advised to upgrade to these updated sssd packages, which upgrade SSSD to upstream version 1.5.1 to correct this issue, and fix the bugs and add the enhancements noted in the Technical Notes.