Vulnerability Note VU#497400

phpBB viewtopic.php fails to properly sanitize input passed to the "highlight" parameter

Overview

phpBB contains an user input validation problem with regard to the parsing of the URL. An intruder can deface a phpBB website, execute arbitrary commands, or gain administrative privileges on a compromised bulletin board.

I. Description

phpBB is an open-source bulletin board. A lack of input validation on the highlight parameter supplied to viewtopic.php may allow a remote attacker to execute arbitrary commands on a vulnerable server. The problem occurs because phpBB does not scan incoming URLs for malicious content when they are decoded.

We have seen reports of exploitation related to this vulnerability.

II. Impact

A remote attacker may be able to deface a phpBB website, execute arbitrary commands, or gain administrative privileges on a compromised bulletin board.

III. Solution

Update

Note that phpBB version 2.0.11 did not adequately correct this vulnerability. The phpBB Development Team has released phpBB version 2.0.16 to fully correct this issue.

Systems Affected

Vendor	Status	Date Notified	Date Updated
phpBB	Vulnerable	21-Dec-2004

References

http://secunia.com/advisories/13239/
http://www.phpbb.com/phpBB/viewtopic.php?f=14&t=240636
http://www.phpbb.com/phpBB/viewtopic.php?f=14&t=240513

Credit

This vulnerability was reported by the phpBB Development Team.

This document was written by Jeff Gennari.

Other Information

Date Public:	2004-11-19
Date First Published:	2004-12-21
Date Last Updated:	2005-06-29
CERT Advisory:
CVE-ID(s):
NVD-ID(s):
US-CERT Technical Alerts:
Metric:	37.97
Document Revision:	33

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