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

http://security.gentoo.org/

Severity:	low
Title:	XFree86, X.org: XDM ignores requestPort setting
Date:	07/05/2004
Bugs:	#53226
ID:	200407-05

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 It has largely been superseded by programs such as GDM and KDM.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	Architecture(s)
x11-base/xfree	<= 4.3.0-r5	>= 4.3.0-r6	All supported architectures
x11-base/xorg-x11	<= 6.7.0	>= 6.7.0-r1	All 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

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 https://bugs.gentoo.org.