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ModSecurity: Denial of Service


1.  Gentoo Linux Security Advisory

Version Information

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


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

2.  Impact Information


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


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).


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


There is no known workaround at this time.


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


Page updated July 02, 2009

Summary: This is a Gentoo Linux Security Advisory

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