Vulnerability Note VU#22091

gpm-root fails to correctly release GID 0 membership for user defined menus

Overview

gpm-root does not properly drop group privileges. Local users can gain group privileges by starting a utility from gpm-root. The gpm package is usually included in Linux distributions, and can be started from the command line or in the startup script /etc/rc.d/rc.local.

I. Description

gpm (General Purpose Mouse) is the program that lets you use the mouse in console mode when not using XWindows. It is usually included in Linux distributions, and can be started from the command line or in the startup script /etc/rc.d/rc.local. gpm-root is a program in the gpm package that allow the use of menus in console mode when Ctrl + Mousebutton is pressed. The gpm-root daemon in gpm version 1.19.1 and earlier lets the user execute any command with elevated group privileges. To exploit this problem, gpm-root must be running on a machine and the user needs both to login to that machine and to have physical access to the keyboard and mouse. When the user selects a utility from a menu, gpm-root starts the associated process with the group and supplementary groups of the gpm-root daemon. A call to setgid fails, providing the user the group privileges of the gpm-root program. The group for the gpm-root binary in the affected installations is root.

II. Impact

A user with console access can use this vulnerability to execute arbitrary commands with elevated group privileges.

III. Solution

Upgrade to gpm version 1.19.2 or later, or apply its setuid(), setgid() and initgruops() related patches.

Systems Affected

Vendor	Status	Date Notified	Date Updated
RedHat	Vulnerable	1-Jun-2001
TurboLinux	Vulnerable	1-Jun-2001

References

http://www.redhat.com/support/errata/RHSA-2000-045-01.html
http://www.securityfocus.com/archive/1/56675
http://www.turbolinux.com/pipermail/tl-security-announce/2000-May/000204.html

Credit

Thanks to Egmont Koblinger for discovering this vulnerability.

This document was written by Andy Moore.

Other Information

Date Public:	2000-03-22
Date First Published:	2001-05-21
Date Last Updated:	2001-06-01
CERT Advisory:
CVE-ID(s):	CVE-2000-0229
NVD-ID(s):	CVE-2000-0229
US-CERT Technical Alerts:
Severity Metric:	7.59
Document Revision:	19

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