Vulnerability Note VU#153653

Linux dump uses environment variables insecurely, allowing for root compromise

Overview

Some implementations of the Linux backup utility, dump, call external programs on remote machines via the RSH environment variable. This may permit an attacker to compromise root if dump is setuid root.

I. Description

Some implementations of the Linux backup utility, dump, permit use of backup devices on remote machines via an access program on the local machine. This access program is identified in the RSH environment variable. The value in the environment variable is not validated for security prior to its use in calling a program. In some implementations, dump is protected setuid root.

II. Impact

By specifying a shell script of their own devising, malicious local users can exploit the setuid protection on dump to secure root access for themselves to execute arbitrary commands.

III. Solution

Apply vendor patches; see the Systems Affected section below.

Remove suid protection from dump.

Systems Affected

Vendor	Status	Date Updated
Conectiva	Not Vulnerable	3-Jul-2001
Debian	Not Vulnerable	23-Jul-2001
Engarde	Not Vulnerable	23-Jul-2001
Hewlett Packard	Unknown	7-Aug-2001
MandrakeSoft	Not Vulnerable	3-Jul-2001
OpenBSD	Not Vulnerable	16-Jul-2001
RedHat	Vulnerable	3-Jul-2001
SGI	Not Vulnerable	16-Jul-2001

References

http://www.kb.cert.org/vuls/id/960877
http://www.securityfocus.com/bid/1871
http://www.linuxsecurity.com/advisories/redhat_advisory-849.html
http://xforce.iss.net/static/5437.php

Credit

This vulnerability was first reported throught discussion on Bugtraq

This document was last modified by Tim Shimeall.

Other Information

Date Public	10/31/2000
Date First Published	08/21/2001 09:07:42 AM
Date Last Updated	08/21/2001
CERT Advisory
CVE Name	CAN-2000-1009
Metric	18.88
Document Revision	9

If you have feedback, comments, or additional information about this vulnerability, please send us email.