Secunia

Microsoft has issued patches for Windows 2000 and XP. These fix a vulnerability in the Workstation service, which can be exploited by malicious people to compromise a vulnerable system.

The problem is an uncontrolled buffer in the logging function of the Windows Workstation Service (WKSSVC.DLL). This can be exploited by malicious people to execute arbitrary code with System privileges.

The vulnerability can be exploited through the DCE/RPC service on UDP and TCP ports 138, 139, and 445.

NOTE: Secunia would normally rate this kind of vulnerability as "Moderately critical", since systems only should expose RPC services to other systems on a LAN.

However, since the vulnerability is similar to the issue exploited by the Blaster worm, which infected numerous systems, the vulnerability has been rated as "Highly critical" instead.

Solution
Patches are available:
Further details available in Customer Area

Provided and/or discovered by
Yuji Ukai, eEye Digital Security

Changelog
Further details available in Customer Area

Original Advisory
Buffer Overrun in the Workstation Service Could Allow Code Execution (828749):
http://www.microsoft.com/technet/security/bulletin/MS03-049.asp

Windows Workstation Service Remote Buffer Overflow:
http://www.eeye.com/html/Research/Advisories/AD20031111.html

Other references
Further details available in Customer Area

Deep Links
Links available in Customer Area