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

2004-07-0600:00:00

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Gentoo Linux Security Advisory GLSA 200407-05

                                        http://security.gentoo.org/

Severity: Low
Title: XFree86, X.org: XDM ignores requestPort setting
Date: July 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largely been superseded by programs such as GDM and KDM.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
-------------------------------------------------------------------

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 &quot;&gt;=x11-base/xfree-4.3.0-r6&quot;
# emerge &quot;&gt;=x11-base/xfree-4.3.0-r6&quot;

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

# emerge sync

# emerge -pv &quot;&gt;=x11-base/xorg-x11-6.7.0-r1&quot;
# emerge &quot;&gt;=x11-base/xorg-x11-6.7.0-r1&quot;

References

[ 1 ] CAN 2004-0419
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-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
[email protected] or alternatively, you may file a bug at
http://bugs.gentoo.org.