ZONEALARM SECURITY ADVISORY
Severity: High

Microsoft DNS Resolution Remote Code Execution Vulnerability

Date Published : 08 August 2006

Date Last Revised : 08 August 2006

Overview : A remote code execution vulnerability exists in Winsock and the DNS Client service.

This vulnerability has been classified as "High Risk." Computer users should take appropriate action to patch vulnerable systems.

Description : Windows Sockets 2 (Winsock) enables programmers to create advanced Internet, intranet, and other network-capable applications to transmit application data across the wire, independent of the network protocol being used.

The Domain Name System (DNS) client service resolves and caches DNS names.

The cause of the vulnerability is an unchecked buffer in the Winsock API and the DNS client layer.

An attacker who successfully exploited this vulnerability could take complete control of an affected system.

Impact : The vulnerability in Winsock could be exploited by an attacker who persuaded a user to open a specially crafted file or view a specially crafted website. There is no way for an attacker to force a user to open a specially crafted file, except potentially through previewing an e-mail message. Additionally, if an application uses the affected API it is possible that it could be exploited during regular usage scenarios that may not require user action.

An anonymous attacker could exploit the vulnerability in the DNS client service by sending a specially crafted DNS communication to an affected client. For an attack to be successful the attacker would either have to be on a subnet between the host and the DNS server or force the target host to make a DNS request to receive a specially crafted record response from an attacking server.

An attack that is successfully exploited would enable an attacker to install malicious code (worm, virus, Trojan horse), read confidential data, or take control over the target system.

Platforms Affected : Please review the Microsoft Security Bulletin MS06041 for a complete list of affected platforms: http://www.microsoft.com/technet/security/bulletin/MS06041.mspx

ZoneAlarm Products That Provide Protection : To ensure the most comprehensive protection, computer users should employ ZoneAlarm Security Suite, or ZoneAlarm Pro. Zone Labs products are not vulnerable to this attack. All Zone Labs security products, including ZoneAlarm, protect the user's system from unauthorized access and intrusions, and alert the user when malicious code attempts to access the network.

Recommended Actions :

ZoneAlarm Family

ZoneAlarm Pro and ZoneAlarm Security Suite protect your system against this vulnerability through "Internet Zone Security" and "Trusted Zone Security". It is recommended that you ensure the following:

  • Internet Zone Security is set to High.
  • Trusted Zone Security is set to Medium.
  • Only trusted hosts are in the 'Trusted' Zone.

Check Point Integrity

Check Point Integrity protects your system against this vulnerability through the following available services:

Classic Firewall Rules

It is recommended that you ensure:

  • Only trusted hosts are in the 'Trusted' Zone.

SmartDefense Program Advisor

SmartDefense Program Advisor automatically blocks malware. It is recommended that you ensure the following:

  • Internet Zone Security is set to High.
  • Trusted Zone Security is set to Medium.

For more information about activating SmartDefense Program Advisor, please refer to CPSA200510 .

Advanced Cooperative Enforcement

  • Use Advanced Cooperative Enforcement to enforce policy upon remote endpoints.

Related Resources :

Install Microsoft patches to remove this vulnerability from the Windows Operating System and other software components: http://windowsupdate.microsoft.com

Review Microsoft Security Bulletin MS06041: http://www.microsoft.com/technet/security/Bulletin/MS06041.mspx

Disclaimer : The information in this advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.

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