A Security Vulnerability in xscreensaver(1) May Display Portions of a Locked Desktop if the Screen is Resized

---

A security vulnerability in xscreensaver(1) may display portions of a locked desktop after being resized:

1. Impact

A security vulnerability in the xscreensaver(1) program may allow users with physical access to an X(5) display running the Xorg(1) X server (or Xnewt(1M) X server for Sun Ray servers)  which has the X Resize and Rotate (RandR) extension loaded to be able to view portions of the locked screen.

2. Contributing Factors

This issue can occur in the following releases:

SPARC Platform

• Solaris 10 without patch 120094-26
  
• OpenSolaris based upon builds snv_01 through snv_111
  

x86 Platform

• Solaris 10 without patch 120095-26
  
• OpenSolaris based upon builds snv_01 through snv_111

Note 1: Solaris 8 and Solaris 9 are not impacted by this issue.

Note 2: This issue only affects systems configured to use the Xorg(1) X server (or Xnewt(1M) X server for Sun Ray servers).  To determine which X Window System display server program (see Xserver(1)) is configured on a Solaris (non-Sun Ray server) system the following command can be run:

    $ svcprop -p options/server svc:/application/x11/x11-server
    /usr/X11/bin/Xorg

To determine which X Window System display server program (see Xserver(1)) is configured on a Sun Ray server the following command can be run:

    $ /opt/SUNWut/bin/utxconfig -l |grep XSERVER
    XSERVER_PREF=Xnewt

Note 3: This issue only affects systems which have used the RandR extension to resize the screen (for example using the xrandr(1) utility). To determine if the RandR extension is loaded, the xdpyinfo(1) utility can be run:

    $ xdpyinfo | grep RANDR
    RANDR

Note 4: OpenSolaris distributions may include additional bug fixes above and beyond the build from which it was derived.  To determine the base build of OpenSolaris, the following command can be used:

    $ uname -v
    snv_86

Note 5:  Only OpenSolaris installations that include the affected binary "/usr/X11/bin/xscreensaver", are impacted by this issue.

3. Symptoms

If the RandR extension has been used to increase the size of the screen, for example using xrandr(1), then xscreensaver(1) will only cover the original screen size.

4. Workaround

To work around the described issue once the screen has been resized using the RandR extension, restarting xscreensaver(1) using the following command:

    $ /usr/X11/bin/xscreensaver-command -restart

will resolve the issue.

5. Resolution

This issue is addressed in the following releases:

SPARC Platform

• Solaris 10 with patch 120094-26 or later
• OpenSolaris based upon builds snv_112 or later
  

x86 Platform

• Solaris 10 with patch 120095-26 or later
• OpenSolaris based upon builds snv_112 or later

For more information on Security Sun Alerts, see Technical Instruction ID 213557.

This Sun Alert notification is being provided to you on an "AS IS" basis. This Sun Alert notification may contain information provided by third parties. The issues described in this Sun Alert notification may or may not impact your system(s). Sun makes no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. This Sun Alert notification contains Sun proprietary and confidential information. It is being provided to you pursuant to the provisions of your agreement to purchase services from Sun, or, if you do not have such an agreement, the Sun.com Terms of Use. This Sun Alert notification may only be used for the purposes contemplated by these agreements.

Copyright 2000-2009 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved.




Attachments

This solution has no attachment