Check Point Advisories

Microsoft SMTP Server DNS Handling (MS04-035; CVE-2004-0840)

Vulnerability
Protection

Check Point Reference:	CPAI-2004-188
Date Published:	23 Feb 2010
Severity:	Critical
Last Updated:	Tuesday 23 February, 2010
Source:
Industry Reference:	CVE-2004-0840
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?
Vulnerability Description	Both Microsoft Windows and Microsoft Exchange include an SMTP service that, among other things, delivers outgoing email messages without the use of an external SMTP server. To perform such email delivery, the SMTP service follows these steps for every recipient email address. A vulnerability exists in the way Microsoft SMTP server handles DNS messages. When a malformed DNS response message is received by the vulnerable software, an unchecked buffer is overrun. An attacker can exploit this vulnerability to inject and execute arbitrary code on a target system. In a simple attack case, When the vulnerability is triggered, target SMTP service will terminate with a memory access violation resulting in a denial of service condition. In a more complicated attack case, arbitrary code execution is possible. If the attacker is successful in injecting code into the vulnerable product, the behaviour of the target will be dependent on the code. The malicious code will be executed with system 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 SMTP Server DNS Handling (MS04-035) 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: SMTP Protection Violation.
Attack Information: Microsoft SMTP Server DNS handling (MS04-035)