Note: This is an archival copy of Security Sun Alert 200863 as previously published on
Latest version of this security advisory is available from as Sun Alert 1000653.1.
Article ID : 1000653.1
Article Type : Sun Alerts (SURE)
Last reviewed : 2007-07-24
Audience : PUBLIC
Copyright Notice: Copyright © 2010, Oracle Corporation and/or its affiliates.

A Security Vulnerability in lbxproxy(1) may Allow Unauthorized Read Access to Files


Release Phase

Solaris 9 Operating System
Solaris 10 Operating System
Solaris 8 Operating System

Bug Id

Date of Resolved Release


A Security Vulnerability in Low Bandwidth X proxy (lbxproxy(1)) may allow a local unprivileged user, the ability to read some data from any file that has group ownership of root on the system.

lbxproxy(1) is used for making connections to the X11 Display Server (Xserver or Xorg) faster over a low bandWidth connection.

Sun acknowledges with thanks, Charles Morris, Old Dominion University, for discovering and reporting this issue.

Contributing Factors

This issue can occur in the following releases:

SPARC Platform

  • Solaris 8 without patch 119067-08
  • Solaris 9 without patch 112785-62
  • Solaris 10 without patch 119059-28

x86 Platform

  • Solaris 8 without patch 119068-08
  • Solaris 9 without patch 112786-51
  • Solaris 10 without patch 119060-27


There are no predictable symptoms that would indicate the described issue has been exploited.


To work around the described issue until patches can be applied, users may wish to turn off the set group ID bit for the "lbxproxy" binary. This can be done by issuing the following command as root user:

    # chmod g-s /usr/openwin/bin/lbxproxy

After the set group ID permissions have been removed the "lbxproxy" command should be run with the "-pn" option so that the program will continue to run after it fails to establish its well-known sockets and instead listen for client connections over TCP.

The DISPLAY environment variable should be set using the format of "hostname:display" instead of just ":display" so that clients will connect over TCP.


This issue is addressed in the following releases:

SPARC Platform

  • Solaris 8 with patch 119067-08 or later
  • Solaris 9 with patch 112785-62 or later
  • Solaris 10 with patch 119059-28 or later

x86 Platform

  • Solaris 8 with patch 119068-08 or later
  • Solaris 9 with patch 112786-51 or later
  • Solaris 10 with patch 119060-27 or later



This solution has no attachment