4.3 - RHSA-2005:481

Problem Description:

Updated openssh packages that fix a potential security vulnerability and various other bugs are now available for Red Hat Enterprise Linux 2.1.

This update has been rated as having low security impact by the Red Hat Security Response Team.

2. Relevant releases/architectures:

Red Hat Enterprise Linux AS (Advanced Server) version 2.1 - i386, ia64 Red Hat Linux Advanced Workstation 2.1 - ia64 Red Hat Enterprise Linux ES version 2.1 - i386 Red Hat Enterprise Linux WS version 2.1 - i386

3. Problem description:

OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation. SSH replaces rlogin and rsh, and provides secure encrypted communications between two untrusted hosts over an insecure network. X11 connections and arbitrary TCP/IP ports can also be forwarded over a secure channel. Public key authentication can be used for "passwordless" access to servers.

The scp protocol allows a server to instruct a client to write to arbitrary files outside of the current directory. This could potentially cause a security issue if a user uses scp to copy files from a malicious server. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2004-0175 to this issue.

These updated packages also correct the following bug:

On systems in which direct ssh access for the root user was disabled by configuration (setting "PermitRootLogin no"), attempts to guess the root password could be judged as sucessful or unsucessful by observing a delay.

Users of openssh should upgrade to these updated packages, which contain backported patches to resolve these issues.

4. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

To update all RPMs for your particular architecture, run:

rpm -Fvh [filenames]

where [filenames] is a list of the RPMs you wish to upgrade. Only those RPMs which are currently installed will be updated. Those RPMs which are not installed but included in the list will not be updated. Note that you can also use wildcards (*.rpm) if your current directory *only* contains the desired RPMs.

Please note that this update is also available via Red Hat Network. Many people find this an easier way to apply updates. To use Red Hat Network, launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate RPMs being upgraded on your system.

If up2date fails to connect to Red Hat Network due to SSL Certificate Errors, you need to install a version of the up2date client with an updated certificate. The latest version of up2date is available from the Red Hat FTP site and may also be downloaded directly from the RHN website:

https://rhn.redhat.com/help/latest-up2date.pxt

5. Bug IDs fixed (http://bugzilla.redhat.com/):

146881 - CAN-2004-0175 malicious ssh server can cause scp to write to arbitrary files 146882 - SSH allows attacker to divine root password