Check Point Advisories

Microsoft IIS WebDAV Extension URL Decoding Security Bypass (CVE-2009-1535)

Vulnerability
Protection

Check Point Reference:	CPAI-2009-130
Date Published:	19 May 2009
Severity:	Critical
Last Updated:	Tuesday 20 September, 2011
Source:
Industry Reference:	CVE-2009-1535
Protection Provided by:	Security Gateway R81, R80, R77, R75, R71, R70, R65
Who is Vulnerable?
Vulnerability Description	Web Distributed Authoring and Versioning (WebDAV) is a set of extensions for HTTP that allow clients to publish, lock, and manage resources on the Web. An elevation of privilege vulnerability has been reported in the Microsoft Windows WebDAV extension for IIS. The vulnerability is due to an error in the Microsoft Windows IIS WebDAV extension that fails to properly decode certain requested URLs. This causes WebDAV to apply an incorrect configuration when handling the request. If the applied configuration allows anonymous access, a malicious request can bypass authentication. To trigger this issue, an attacker may create a specially crafted HTTP request and send it to a website that requires authentication. Successful exploitation may allow the attacker to gain unauthorized access to protected resources.

Protection Overview

This protection will detect and block WebDAV requests attempting to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R80 / R77 / R75 / R71 / R70 / R65

In the IPS tab, click Protections and find the Microsoft IIS WebDAV Extension URL Decoding Security Bypass protection using the Search tool and Edit the protection's settings.
Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name: Web Server Enforcement Violation.
Attack Information: Microsoft IIS WebDAV extension URL decoding security bypass