Silicon Graphics Computer Systems IRIX lp Vulnerability

Original issue date: April 10, 1992
Last revised: September 19, 1997
Attached copyright statement

A complete revision history is at the end of this file.

The Computer Emergency Response Team/Coordination Center (CERT/CC) has received information concerning a method of unauthorized root access in the lp software in Silicon Graphics Computer Systems (SGI) IRIX operating systems.  This vulnerability is present in all current versions of IRIX.

Silicon Graphics Computer Systems and the CERT/CC strongly recommend that sites take immediate action to eliminate this vulnerability from their systems.

This vulnerability will be fixed in IRIX 4.0.5 and is NOT present in any version of the Trusted IRIX/B product.

I. Description

When IRIX pre-4.0.5 systems are installed or updated using either the basic system software ("eoe1.sw.unix") or the system manager software ("eoe2.sw.vadmin") media, a vulnerability is introduced in the lp software.

II. Impact

Any user logged into the system can gain root access.

III. Solution

As root, execute the following commands:
        # cd /usr/lib
        # chmod a-s,go-w lpshut lpmove accept reject lpadmin
        # chmod go-ws lpsched vadmin/serial_ports vadmin/users vadmin/disks
        # cd /usr/bin
        # chmod a-s,go-w disable enable
        # chmod go-ws cancel lp lpstat
If the eoe2.sw.vadmin software is not installed, you may ignore any warning messages from chmod such as:

"chmod: WARNING: can't access vadmin/serial_ports"

If system software should ever be reinstalled from pre-4.0.5 media or restored from a backup tape created before the patch was applied, repeat the above procedure before enabling logins by normal users.

The CERT/CC would like to thank Silicon Graphics Computer Systems for bringing this security vulnerability to our attention and for their quick response to this problem.

This document is available from:

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Copyright 1992 Carnegie Mellon University.

Revision History
September 19,1997  Attached copyright statement