Vulnerability Note VU#349019

Tripwire vulnerable to arbitrary file overwriting via symlink redirection of temporary file

Overview

Tripwire is a file integrity verification utility for Unix and Linux operating systems. In some implementations, tripwire opens insecure temporary files with predictable names in publically-writable directories. Using a symbolic link attack, a local intruder may overwrite or create arbitrary files on machines running tripwire.

I. Description

Tripwire opens temporary files in /tmp using predictable names without first checking for prior existence or ownership of these files. The files are opened when building or updating tripwire's database of file checksums.

II. Impact

By creating symbolic links with appropriate names within a very tight time window, a local attacker may be able to redirect the data sent to the temporary file to arbitrary files on machines running tripwire. Since tripwire normally is executed by the system administrator, file protections will not apply. The file overwrite may result in disabling of system services, crashing the machine, or disabling of system protections.

III. Solution

Apply vendor patches; see the Systems Affected section below.

Clear /tmp prior to execution of tripwire.

Systems Affected

Vendor	Status	Date Notified
MandrakeSoft	Vulnerable	27-Sep-2001
sourceforge	Vulnerable	27-Sep-2001
Tripwire	Vulnerable	29-Oct-2001

References

http://sourceforge.net/projects/tripwire/
http://www.tripwire.com
http://securityfocus.com/bid/3003
http://www.linuxsecurity.com/advisories/mandrake_advisory-1502.html

Credit

This vulnerability was first discovered by Jamo Huuskonen.

This document was last modified by Tim Shimeall.

Other Information

Date Public:	2001-07-09
Date First Published:	2001-11-15
Date Last Updated:	2001-11-15
CERT Advisory:
CVE-ID(s):
NVD-ID(s):
US-CERT Technical Alerts:
Severity Metric:	5.85
Document Revision:	10

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