ModSecurity: Denial of Service

Security Team Contact Address

Updated July 02, 2009

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200907-02 / mod_security
Release Date	July 02, 2009
Latest Revision	July 02, 2009: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
www-apache/mod_security	< 2.5.9	>= 2.5.9	All supported architectures

Related bugreports: #262302

Synopsis

Two vulnerabilities in ModSecurity might lead to a Denial of Service.

2. Impact Information

Background

ModSecurity is a popular web application firewall for the Apache HTTP server.

Description

Multiple vulnerabilities were discovered in ModSecurity:

Juan Galiana Lara of ISecAuditors discovered a NULL pointer dereference when processing multipart requests without a part header name (CVE-2009-1902).
Steve Grubb of Red Hat reported that the "PDF XSS protection" feature does not properly handle HTTP requests to a PDF file that do not use the GET method (CVE-2009-1903).

Impact

A remote attacker might send requests containing specially crafted multipart data or send certain requests to access a PDF file, possibly resulting in a Denial of Service (crash) of the Apache HTTP daemon. NOTE: The PDF XSS protection is not enabled by default.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All ModSecurity users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=www-apache/mod_security-2.5.9"

4. References