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.

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