Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
Description
Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
This vulnerability exists due to errors when processing malformed packets during NTLM authentication procedures. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious network request to the vulnerable system. If successful, the attacker could cause the system to fail, resulting in a DoS condition.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates that correct it.
Warning Indicators
The following Microsoft systems are affected:
Windows XP SP3
Windows XP Professional x64 Edition SP2
Windows Server 2003 SP2
Windows Server 2003 x64 Edition SP2
Windows Server 2003 for Itanium-based Systems SP2
Windows Vista SP2
Windows Vista x64 Edition SP2
Windows Server 2008 for 32-bit Systems SP2
Windows Server 2008 for x64-based Systems SP2
Windows Server 2008 for Itanium-based Systems SP2
Windows Server 2008 R2 for x64-based Systems
Windows Server 2008 R2 for Itanium-based Systems
IntelliShield Analysis
In order to exploit this vulnerability, an attacker may require access to trusted, internal networks. Sites will likely restrict access from external networks to reach internal hosts.
If an exploit is successful, the attacker could cause the system to fail and restart, resulting in a DoS condition, preventing access to system resources by authorized users. Repeated attacks could render the system completely unavailable.
Administrators should note that Windows XP and Windows Server 2003 systems are vulnerable only if the Extended Protection for Authentication update (KB968389) has been applied.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the October 2009 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin Release for October 2009
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS09-059
Impact
An unauthenticated, remote attacker could exploit this vulnerability to cause the system to become unresponsive, resulting in a DoS condition.
Technical Information
This vulnerability exists due to errors when processing malformed packets during NTLM authentication procedures. The Windows Local Security Authority Subsystem Service (LSASS) fails to handle packets received during anonymous authentication requests. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious network request to the system. The processing of the request could trigger an error condition, causing the service to fail, automatically restarting the system and resulting in a DoS condition.
Safeguards
Administrators are advised to apply the available software updates.
Administrators are advised to restrict local system access.
Administrators are advised to restrict network access to affected systems.
Administrators may consider removing the KB968389 update from Windows XP or Windows Server 2003 systems.
Administrators are advised to monitor critical systems.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Patches/Software
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Signatures
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
Home Edition Base, SP1, SP2, SP3 | Professional Edition Base, SP1, SP2, SP3 | Professional x64 (AMD/EM64T) Base
Associated Products:
N/A
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