Microsoft Security Bulletin MS00-024

This vulnerability involves a registry key used by the CryptoAPI Base CSPs to specify the driver DLL for a hardware accelerator. By design, such a DLL would have access to users' public and private keys. Although only administrators should have permission to add such a DLL, the permissions on the key actually would allow any user who could interactively log onto the machine to do so. By writing a bogus DLL and installing it, a malicious user could compromise the keys of other users who subsequently used the machine.

The machines primarily at risk would be workstations and terminal servers. If normal security recommendations are followed, normal users will not be allowed to interactively log onto domain controllers, web servers, database servers, ERP servers, and other security-critical machines. Windows NT auditing could be used to determine who changed the key's value. A tool is available that resets the permissions on the affected key to the correct default values. In addition, it incorporates the functionality of the tool provided in Microsoft Security Bulletin MS00-008.

Affected Software Versions

• Microsoft Windows NT 4.0 Workstation
• Microsoft Windows NT 4.0 Server
• Microsoft Windows NT 4.0 Server, Enterprise Edition
• Microsoft Windows NT 4.0 Server, Terminal Server Edition

  NOTE: Windows 2000 is not affected by this vulnerability.

Vulnerability Identifier: CAN-2000-0259

• X86:   http://www.microsoft.com/downloads/details.aspx?FamilyId=AB792154-6BBD-4D27-9C87-8C7689BD908F&displaylang=en
• Alpha: http://www.microsoft.com/downloads/details.aspx?FamilyId=AECBDFA7-D641-4FE7-A799-9D5C4F103DB2&displaylang=en

  Note: This tool also covers the vulnerability described in MS00-008.

  Note: Additional security patches are available at the Microsoft Download Center