Updated openssh packages that fix a security issue and various bugs are now available. This update has been rated as having moderate security impact by the CentOS Security Response Team.
OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation. These packages include the core files necessary for both the OpenSSH client and server. A flaw was found in the way the ssh server wrote account names to the audit subsystem. An attacker could inject strings containing parts of audit messages, which could possibly mislead or confuse audit log parsing tools. (CVE-2007-3102) A flaw was found in the way the OpenSSH server processes GSSAPI authentication requests. When GSSAPI authentication was enabled in the OpenSSH server, a remote attacker was potentially able to determine if a username is valid. (CVE-2006-5052) The following bugs in SELinux MLS (Multi-Level Security) support has also been fixed in this update: * It was sometimes not possible to select a SELinux role and level when logging in using ssh. * If the user obtained a non-default SELinux role or level, the role change was not recorded in the audit subsystem. * In some cases, on labeled networks, sshd allowed logins from level ranges it should not allow. The updated packages also contain experimental support for using private keys stored in PKCS#11 tokens for client authentication. The support is provided through the NSS (Network Security Services) library. All users of openssh should upgrade to these updated packages, which contain patches to correct these issues.