Microsoft Windows contains a vulnerability that could allow a local attacker to gain escalated privileges or cause a denial of service condition. Updates are available.
Description
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.
Warning Indicators
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
IntelliShield Analysis
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 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 improving memory allocation.
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS09-041
Impact
A local attacker could exploit this vulnerability to execute arbitrary code with elevated privileges, possibly resulting in a complete system compromise. On some systems, the attacker could trigger a DoS condition.
Technical Information
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.
Safeguards
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.
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, SP2
Associated Products:
N/A
Alerts and bulletins on the Cisco Security Intelligence Operations Portal are highlighted by analysts in the
Cisco Threat Operations Center and represent a subset of the comprehensive content that is available through Cisco Security IntelliShield Alert Manager Service.
This customizable threat and vulnerability alert service provides security staff with access to timely, accurate, and credible information about threats and vulnerabilities that may affect their environment. Cisco is pleased to offer a free trial of the service.
To register for full access, please visit the IntelliShield trial registration page.
LEGAL DISCLAIMER The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.
