Microsoft Windows contains a vulnerability that could allow a local attacker to gain escalated privileges or cause a denial of service (DoS) condition.
This vulnerability exists due to errors when handling malformed Remote Procedure Call (RPC) messages. A local attacker could exploit this vulnerability by sending malicious RPC requests to the vulnerable system. If successful, the attacker could execute arbitrary code with elevated privileges.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates that correct it.
Indicators of Compromise
The following Microsoft systems are affected:
Windows XP SP3 and prior
Windows XP Professional x64 Edition SP2 and prior
Windows Server 2003 SP2 and prior
Windows Server 2003 x64 Edition SP2 and prior
Windows Server 2003 Itanium-based Systems with SP2 and prior
Windows Vista SP2 and prior
Windows Vista x64 Edition SP2 and prior
Windows Server 2008 for 32-bit Systems SP2 and prior
Windows Server 2008 for x64-based Systems SP2 and prior
Windows Server 2008 for Itanium-based Systems SP2 and prior
This vulnerability exists due to errors when handling malformed RPC messages. The processing of a malicious RPC message could cause the affected system to free previously deallocated memory objects, resulting in a double-free error that could trigger memory corruption. A local attacker could exploit this vulnerability by submitting a malicious RPC request to the vulnerable system. When processed, the request could trigger a double-free error that could corrupt memory and allow the attacker to execute arbitrary code with the privileges of the Workstation service, typically LocalSystem.
An attacker must possess credentials sufficient to log on locally to the system in order to exploit this vulnerability. The attacker must send malicious RPC requests to the Workstation service in order to accomplish an exploit. If an exploit is successful, the attacker could execute code resulting in a complete system compromise. However, because of the technical challenges in developing an exploit, it may be difficult to create exploits for different system platforms. Additionally, code execution may only be possible on Windows XP and Windows Server 2003 platforms. An attacker may only be able to accomplish a DoS condition on Windows Vista or Windows Server 2008 systems.
If an attacker holds credentials sufficient for local authentication, the attacker could exploit this vulnerability remotely in some circumstances. If the system allows remote File and Printer Sharing, an authenticated, remote attacker could exploit the vulnerability over the network.
The update available from Microsoft corrects this vulnerability by improving memory allocation.
Administrators are advised to apply the appropriate software updates.
Administrators are advised to restrict network access to affected systems on TCP ports 139 and 445.
Administrators are advised to restrict system access to trusted users.
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.
Microsoft has released a security bulletin at the following link: MS09-041
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.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.