Updated openssh packages that fix a security issue, bugs, and add support
for recording login user IDs for audit are now available for CentOS
Enterprise Linux 4.
This update has been rated as having moderate security impact by the Red
Hat Security Response Team.
OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation.
An error in the way OpenSSH handled GSSAPI credential delegation was
discovered. OpenSSH as distributed with CentOS Linux 4 contains
support for GSSAPI user authentication, typically used for supporting
Kerberos. On OpenSSH installations which have GSSAPI enabled, this flaw
could allow a user who sucessfully authenticates using a method other than
GSSAPI to be delegated with GSSAPI credentials. The Common Vulnerabilities
and Exposures project (cve.mitre.org) has assigned the name CAN-2005-2798
to this issue.
Additionally, the following bugs have been addressed:
The ssh command incorrectly failed when it was issued by the root user with
a non-default group set.
The sshd daemon could fail to properly close the client connection if
multiple X clients were forwarded over the connection and the client
The sshd daemon could bind only on the IPv6 address family for X forwarding
if the port on IPv4 address family was already bound. The X forwarding did
not work in such cases.
This update also adds support for recording login user IDs for the auditing
service. The user ID is attached to the audit records generated from the
All users of openssh should upgrade to these updated packages, which
contain backported patches to resolve these issues.