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AUSCERT External Security Bulletin Redistribution
ESB-2000.334 -- FreeBSD-SA-00:65
xfce allows local X session compromise
9 November 2000
AusCERT Security Bulletin Summary
Vendor: FreeBSD Ports Collection
Operating System: FreeBSD
Impact: Reduced Security
Access Required: Local
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FreeBSD-SA-00:65 Security Advisory
Topic: xfce allows local X session compromise
Credits: Nicholas Brawn <nickbrawn@ONETEL.COM>
Affects: Ports collection prior to the correction date.
Vendor status: Updated version released
FreeBSD only: NO
xfce is a window manager/desktop environment for the X Windows system.
II. Problem Description
Versions of xfce prior to 3.52 contain a startup script which
incorrectly allows access to the X display to all other users on the
local system. Such users are able to monitor and control the contents
of the display window as well as monitoring input from keyboard and
mouse devices. For example, this allows them to monitor passphrases
typed into a terminal window, among other possibilities.
The xfce port is not installed by default, nor is it "part of FreeBSD"
as such: it is part of the FreeBSD ports collection, which contains
over 4100 third-party applications in a ready-to-install format. The
ports collections shipped with FreeBSD 3.5.1 and 4.1.1 are vulnerable
to this problem since it was discovered after the releases, but it was
corrected prior to the release of FreeBSD 4.2.
FreeBSD makes no claim about the security of these third-party
applications, although an effort is underway to provide a security
audit of the most security-critical ports.
Local users can monitor and control the contents of the X display
running xfce, as well as input devices such as mice and keyboards.
Deinstall the xfce port/package, if you you have installed it, or
remove the lines containing 'xhost +$HOSTNAME' in the following files:
One of the following:
1) Upgrade your entire ports collection and rebuild the xfce port.
2) Deinstall the old package and install a new package dated after the
correction date, obtained from the following directories:
3) download a new port skeleton for the xfce port from:
and use it to rebuild the port.
4) Use the portcheckout utility to automate option (3) above. The
portcheckout port is available in /usr/ports/devel/portcheckout or the
package can be obtained from:
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