search menu icon-carat-right cmu-wordmark

CERT Coordination Center

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

Vulnerability Note VU#349019

Original Release Date: 2001-11-15 | Last Revised: 2001-11-15

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.

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.

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.

Solution

Apply vendor patches; see the Systems Affected section below.

Clear /tmp prior to execution of tripwire.

Vendor Information

349019
 
Affected   Unknown   Unaffected

MandrakeSoft

Notified:  July 09, 2001 Updated:  September 27, 2001

Status

  Vulnerable

Vendor Statement

http://www.linuxsecurity.com/advisories/mandrake_advisory-1502.html

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.

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

Tripwire

Notified:  October 09, 2001 Updated:  October 29, 2001

Status

  Vulnerable

Vendor Statement

The vulnerability exists in Tripwire versions prior to 2.4.0 and commercial customers should be encouraged to upgrade to the most current shipping product, version 2.4.2.  Open Source and ASR users should upgrade to Open Source version 2.3.1-2 or later (see http://www.sourceforge.net/projects/tripwire for the latest information) or apply the documented code fixes to their particular release and recompile. In version Commercial 2.4.x and Open Source 2.3.1-2, the O_EXCL flag is used
when opening temporary files, to insure the temporary file does not already exist, thus making the exploit much more difficult.

In version, 2.4.0 and greater, we have implemented a variable that allows a user to specify a Tripwire specific temp directory whose permissions can be set to only be writeable by tripwire (typically run as root). The traditional /tmp directory is writeable  by world which enables the various exploits. Setting TEMPDIRECTORY to a directory whose permissions are closely controlled removes any possibility of a non-root user using temp directory exploits to modify tripwire behavior.

Tripwire, Inc. has been actively developing a commercial version of Tripwire for Servers which is fully verified and maintained for a wide variety of hardware and software platforms. We recommend the use of Tripwire's commercial software in any environment where secure, supported, commercial quality software is required. For more information about Tripwire's commercial data and network integrity solutions, go to www.tripwire.com.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.

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

sourceforge

Notified:  January 16, 2001 Updated:  September 27, 2001

Status

  Vulnerable

Vendor Statement

corrected version available at http://sourceforge.net/projects/tripwire/.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.

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


CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A

References

Acknowledgements

This vulnerability was first discovered by Jamo Huuskonen.

This document was last modified by Tim Shimeall.

Other Information

CVE IDs: None
Severity Metric: 5.85
Date Public: 2001-07-09
Date First Published: 2001-11-15
Date Last Updated: 2001-11-15 16:25 UTC
Document Revision: 10

Sponsored by the Department of Homeland Security Office of Cybersecurity and Communications.