This article was previously published under Q259496
This article has been archived. It is offered "as is" and will no longer be updated.
On a shared computer, it may be possible for a malicious user to interactively log on to the computer and compromise the security of the cryptographic keys of other users who subsequently log on to the same computer.
This vulnerability involves a registry key that is used to specify the dynamic-link library (DLL) for a hardware accelerator in the default Cryptographic service providers (CSPs) that are included with Cryptography Application Programming Interface (CryptoAPI). By design, such a DLL has access to users' public and private keys. Although only administrators should have permission to add such a DLL, the permissions on the key could allow any user who can interactively log on to the computer to do so. By writing a DLL and installing it, a malicious user could compromise the keys of other users who subsequently use the computer.
Windows NT 4.0
To resolve this problem, obtain the individual package referenced below or obtain the Windows NT 4.0 Security Rollup Package. For additional information on the SRP, click the article number below to view the article in the Microsoft Knowledge Base:
299444 Post-Windows NT 4.0 Service Pack 6a Security Rollup Package (SRP)
The following files are available for download from the MicrosoftDownload Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.The English version of this fix should have the following file attributes or later:
Date Time Size File name Platform ------------------------------------------------ 04/11/00 08:19p 41,744 Regacl40.exe Intel 04/12/00 03:43p 95,504 Regacl40.exe Alpha
Microsoft Windows NT Server version 4.0, Terminal Server Edition
To resolve this problem, obtain the Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package (SRP). For additional information about the SRP, click the article number below to view the article in the Microsoft Knowledge Base:
317636 Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package
Microsoft has confirmed that this problem may cause a degree of security vulnerability in Windows NT 4.0.
The computers primarily at risk are workstations and servers running Terminal Server Edition. If you follow typical security recommendations, typical users are not allowed to interactively log on to domain controllers, Web servers, database servers, ERP servers, and other security-critical computers. A tool is available that resets the permissions on the key to the correct default values. In addition, it incorporates the functionality of the tool provided in Microsoft Security Bulletin MS00-008 located at the following Microsoft Web site:
Microsoft Windows NT Server 4.0, Terminal Server Edition, Microsoft Windows NT Workstation 4.0 Developer Edition, Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows NT Server 4.0 Enterprise Edition, Microsoft BackOffice Server 4.0, Microsoft BackOffice Small Business Server 4.0