Microsoft Windows contains a vulnerability in the WINS Server component that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are available.
Description
Microsoft Windows contains a vulnerability in the WINS Server component that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to improper boundary checking on input processed by the WINS Server. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious WINS request to the vulnerable server. An exploit could allow the attacker to execute arbitrary code on the vulnerable system.
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 2000 SP4 and prior
Windows Server 2003 SP2 and prior
Windows Server 2003 x64 Edition SP2 and prior
Windows Server 2003 for Itanium-based Systems SP2 and prior
IntelliShield Analysis
Attackers do not require authentication to exploit this vulnerability. However, the attacker may require access to trusted, internal networks to send a malicious request to the affected system, reducing the potential for external attacks. An exploit could allow the attacker to execute arbitrary code on the affected system, possibly resulting in a complete system compromise.
Because the WINS Server is not installed by default on affected systems, the potential for widespread exploitation may be decreased. WINS services may be installed in only a few environments, leaving no vector for exploitation on systems that do not have the WINS Server component installed.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the August 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 August 2009
The update available from Microsoft corrects this vulnerability by performing proper length checking.
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS09-039
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the elevated privileges of the WINS Server, possibly resulting in a complete system compromise.
Technical Information
The vulnerability is due to improper boundary checking on input processed by the WINS Server. The processing of overly large input could trigger a heap-based buffer overflow, resulting in memory corruption. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious WINS network message to the vulnerable system. The processing of the request could result in memory corruption, which the attacker could use to execute arbitrary code with the elevated privileges of the WINS Server process.
Safeguards
Administrators are advised to apply the appropriate software updates.
Administrators are advised to restrict network access on TCP and UDP port 42 to affected systems.
Administrators may consider disabling the WINS Server component.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected 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
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