Check Point Advisories

Microsoft Windows CSRSS HardError Message Box (MS07-021; CVE-2006-6696)

Vulnerability
Protection

Check Point Reference:	CPAI-2006-318
Date Published:	23 Mar 2010
Severity:	Critical
Last Updated:	Tuesday 23 March, 2010
Source:
Industry Reference:	CVE-2006-6696
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?
Vulnerability Description	The Microsoft Windows operating system is one of the most popular systems in use on workstations, home computers, and servers. The operating system is split into several subsystems one of which is the user space subsystem called the Client/Server Runtime Server Subsystem (CSRSS). The CSRSS contains support for console windows, creating and deleting threads, as well as some parts of the 16-bit virtual MS-DOS environment. The service is implemented by the csrss.exe binary executable which runs under user mode with System level privileges. There exists a memory corruption vulnerability in Microsoft Windows. The vulnerability is due to improper handling of "HardError" messages in Windows Client/Server Runtime Server Subsystem (CSRSS). A remote unauthenticated attacker can exploit this vulnerability by enticing the target user to visit a malicious website using Internet Explorer. Successful exploitation of this vulnerability may allow the remote attackers to execute arbitrary code with the privileges of the System. In an attack case where code injection is not successful, it results in a kernel error condition which is also known as the "Blue Screen of Death". The vulnerable system may reboot or halt which results in a denial of service condition. In a more sophisticated attack where code injection is successful, the behavior of the target is entirely dependent on the intended function of the injected code. The code in such a case would execute within the security context of the System level privileges.

Protection Overview

This protection will detect and block attempts 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

In the IPS tab, click Protections and find the Microsoft Windows CSRSS HardError Message Box (MS07-021) 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: Content Protection Violation.
Attack Information: Microsoft Windows CSRSS hardError message box (MS07-021)