RHSA-2003:259 - Security Advisory

Topic

Updated GDM packages are available which correct a local crash if XDMCP is
enabled.

Description

GDM is the GNOME Display Manager for X.

Two bugs have been found in the X Display Manager Control Protocol (XDMCP)
which could allow a denial of service attack (DoS) by crashing the gdm
daemon. The Common Vulnerabilities and Exposures project (cve.mitre.org)
has assigned the names CAN-2003-0548 and CAN-2003-0549 to these issues.

This attack is only possible if XDMCP is enabled. XDMCP is not enabled by
default in Red Hat Enterprise Linux distributions. In addition is
documented best practise that XDMCP should only ever be run on trusted
networks.

Users of XDMCP in GDM should upgrade to these erratum packages which
contain backported security fixes are are not vulnerable to these issues.

Note that Red Hat Enterprise Linux 2.1 is not vulnerable to CAN-2003-0547,
a vulnerability that allows a local user to read any text file, as it did
not have the "examine session errors" feature.

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.

Affected Products

• Red Hat Enterprise Linux Server 2 ia64
• Red Hat Enterprise Linux Server 2 i386
• Red Hat Enterprise Linux Workstation 2 ia64
• Red Hat Enterprise Linux Workstation 2 i386

Fixes

• BZ - 102452 - CAN-2003-0548/9 XDMCP GDM DoS

CVEs

• CVE-2003-0549
• CVE-2003-0548

References

(none)