[ GLSA 200407-05 ] XFree86, X.org: XDM ignores requestPort

[pahud]

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Gentoo Linux Security Advisory GLSA 200407-05
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http://security.gentoo.org/
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Severity: Low
Title: XFree86, X.org: XDM ignores requestPort setting
Date: July 05, 2004
Bugs: #53226
ID: 200407-05

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Synopsis
========

XDM will open TCP sockets for its chooser, even if the
DisplayManager.requestPort setting is set to 0. This may allow
authorized users to access a machine remotely via X, even if the
administrator has configured XDM to refuse such connections.

Background
==========

The X Display Manager (XDM) is a program which provides a graphical
login prompt to users on the console or on remote X terminals. It has
largely been superseded by programs such as GDM and KDM.

Affected packages
=================

-------------------------------------------------------------------
Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 x11-base/xfree <= 4.3.0-r5 >= 4.3.0-r6
2 x11-base/xorg-x11 <= 6.7.0 >= 6.7.0-r1
-------------------------------------------------------------------
2 affected packages on all of their supported architectures.
-------------------------------------------------------------------

Description
===========

XDM will open TCP sockets for its chooser, even if the
DisplayManager.requestPort setting is set to 0. Remote clients can use
this port to connect to XDM and request a login window, thus allowing
access to the system.

Impact
======

Authorized users may be able to login remotely to a machine running
XDM, even if this option is disabled in XDM's configuration. Please
note that an attacker must have a preexisting account on the machine in
order to exploit this vulnerability.

Workaround
==========

There is no known workaround at this time. All users should upgrade to
the latest available version of X.

Resolution
==========

If you are using XFree86, you should run the following:

# emerge sync

# emerge -pv ">=x11-base/xfree-4.3.0-r6"
# emerge ">=x11-base/xfree-4.3.0-r6"

If you are using X.org's X11 server, you should run the following:

# emerge sync

# emerge -pv ">=x11-base/xorg-x11-6.7.0-r1"
# emerge ">=x11-base/xorg-x11-6.7.0-r1"

References
==========

[ 1 ] CAN 2004-0419
http://cve.mitre.org/cgi-bin/cvename.cg ... -2004-0419
[ 2 ] XFree86 Bug
http://bugs.xfree86.org/show_bug.cgi?id=1376

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

http://security.gentoo.org/glsa/glsa-200407-05.xml

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2004 Gentoo Technologies, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/1.0

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