Vulnerability Note VU#354648

Microsoft Windows NT 4.0/TSE Winsock2ProtocolCatalogMutex has insecure permissions

Original Release date: 06 Feb 2001 | Last revised: 06 Feb 2001


A mutex controlling access to resources required for networking on Windows NTMicrosoft Windows NT 4.0 and Microsoft Windows NT 4.0, Terminal Server Edition, has inappropriate permissions.


In general terms, a mutex is an object used to control access to a resource (e.g. a printer, disk, segment of memory, data structure, etc.) so that only a single "consumer" (e.g. a process or program) can have access to the resource at any one time. That is, it enforces a policy of mutual exclusion between would-be consumers of a resource, typically so that access to the resource can by properly synchronized. A process that has acess to a resource controlled by a mutex is said to have locked the mutex. A process that "wants" a resource locked by another process is said to be waiting on the mutex, or waiting on a locked mutex.

Microsoft Windows NT 4.0 and Microsoft Windows NT 4.0, Terminal Server Edition uses a mutex named Winsock2ProtocolCatalogMutex to control access to resources required for NT networking to function properly. On unpatched versions of Windows, the mutex is protected inappropriately so that ordinary users can disable access to the mutex by changing the ACL on the mutex , or lock the mutex indefinitely. In either case, the intruder can effectively disable network access on that machine.


Intruders who can log in locally can effectively disable network access for the machine.


Apply a patch as described in MS01-003.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
MicrosoftAffected24 Jan 200105 Feb 2001
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Our thanks to Arne Vidstrom who discovered the problem, and Microsoft for the information provided in their bulletin.

This document was written by Shawn V. Hernan.

Other Information

  • CVE IDs: CAN-2001-0006
  • Date Public: 24 Jan 2001
  • Date First Published: 06 Feb 2001
  • Date Last Updated: 06 Feb 2001
  • Severity Metric: 2.16
  • Document Revision: 6


If you have feedback, comments, or additional information about this vulnerability, please send us email.