Additional technical information is available to describe the Microsoft Windows License Logging Service heap overflow vulnerability. New technical details suggest that a successful exploit may be unlikely.
Microsoft Windows 2000 contains a vulnerability in the License Logging Service that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability exists because affected systems do not properly handle malformed RPC requests that are submitted to the service. An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with SYSTEM privileges.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates.
Microsoft Windows 2000 systems with SP4 or prior are affected by this vulnerability. The vulnerability only affects server operating systems; Windows 2000 Professional does not contain the vulnerable service.
The License Logging Service is enabled by default on Windows Server 2000.
This vulnerability affects systems running the License Logging Service, which is used to manage licenses under a Client Access License (CAL) licensing model. As a result, it does not run on workstation operating systems. Further, domains that are not licensed under a CAL model, or servers in a domain that are not running the service, are not affected.
Microsoft has corrected this vulnerability by validating string lengths in RPC calls to the service.
Microsoft has released a security bulletin at the following link: MS09-064
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with SYSTEM privileges.
The vulnerability exists because the system incorrectly handles Remote Procedure Calls (RPC) to the llsrv.exe License Logging Service of Microsoft Windows. Arguments that are supplied to the LlsrLicenseRequestW method are not sufficiently checked for NULL byte termination.
An unauthenticated, remote attacker could exploit this lack of validation of NULL byte termination to concatenate a call to the lstrcatW method within the arguments that are supplied to the LlsrLicenseRequestW method. An exploit could lead to a heap-based overflow, to allow the attacker to execute arbitrary code with SYSTEM privileges.
Administrators are advised to apply the appropriate updates.
Administrators are advised to disable the License Logging Service on systems that do not require it for maintaining licensing compliance.
Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.
Administrators are advised to implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
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 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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