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MS.DNS.LLMNR.Query.Stack.Overflow

Release Date

Apr 13, 2011

Severity

critical

Impact

If an attacker could gain access to the network and create a custom program to send specially crafted LLMNR broadcast queries to the targetted systems, the vulnerability could allow remote code execution.

Description

At April 12, 2011, Microsoft released a Security Bulletin MS11-030 regarding a privately reported vulnerability in Windows DNS resolution. The vulnerability could allow remote code execution if an attacker could gain access to the network and create a custom program to send specially crafted LLMNR broadcast queries to the targetted systems. Firewall best practices and standard default firewall configurations can help protect networks from attacking that originate outside the enterprise perimeter. Best practices advise that systems that are connected to the Internet have a minimal number of ports exposed. In such case, the LLMNR ports should be blocked from the Internet.

Neel Mehta of Google Inc. reported the DNS Query Vulnerability: A remote code execution vulnerability exists in the way that the DNS client service handles specially crafted LLMNR queries. An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the NetworkService account. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.(CVE-2011-0657)

This security update is rated Critical for all supported editions of Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2. The security update is rated Important for all supported editions of Windows XP and Windows Server 2003.

Affected Products

Windows Vista Service Pack 1 and Windows Vista Service Pack 2
Windows Vista x64 Edition Service Pack 1 and Windows Vista x64 Edition Service Pack 2
Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for Itanium-based Systems and Windows Server 2008 for Itanium-based Systems Service Pack 2
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems and Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems and Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for Itanium-based Systems and Windows Server 2008 R2 for Itanium-based Systems Service Pack 1

Recommended Actions

Most customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871 (http://support.microsoft.com/kb/294871).

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update (http://go.microsoft.com/fwlink/?LinkID=40747) service.

For FortiGate users, turning on these IPS signatures can prevent exploitation of this vulnerability:
MS.DNS.LLMNR.Query.Stack.Overflow

Coverage

IPS
VCM

Common Vulnerabilities and Exposures (CVE)

CVE-2011-0657

Reference/s

http://www.securityfocus.com/bid/47242 (BugTraq)
http://technet.microsoft.com/en-us/security/bulletin/MS11-030.mspx (MS-ID)

Reference: VID-26528