RHSA-2005:106 - Security Advisory

Topic

Updated openssh packages that fix a potential security vulnerability and
various other bugs are now available for Red Hat Enterprise Linux 3.

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

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 bugs:

On systems where 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.

On systems where the privilege separation feature was turned on, the user
resource limits were not correctly set if the configuration specified to
raise them above the defaults. It was also not possible to change an
expired password.

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

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

Affected Products

• Red Hat Enterprise Linux Server 3 x86_64
• Red Hat Enterprise Linux Server 3 ia64
• Red Hat Enterprise Linux Server 3 i386
• Red Hat Enterprise Linux Workstation 3 x86_64
• Red Hat Enterprise Linux Workstation 3 ia64
• Red Hat Enterprise Linux Workstation 3 i386
• Red Hat Enterprise Linux Desktop 3 x86_64
• Red Hat Enterprise Linux Desktop 3 i386
• Red Hat Enterprise Linux for IBM z Systems 3 s390x
• Red Hat Enterprise Linux for IBM z Systems 3 s390
• Red Hat Enterprise Linux for Power, big endian 3 ppc

Fixes

• BZ - 120147 - CAN-2004-0175 malicious ssh server can cause scp to write to arbitrary files
• BZ - 124602 - OpenSSH does not allow users to change expired passwords when privsep is used
• BZ - 141642 - SSH allows attacker to divine root password

CVEs

• CVE-2004-0175

References

(none)