Microsoft Security Bulletin (MS00-032)
Patch and Tool Available for "Protected Store Key Length" Vulnerability
Originally Posted: June 01, 2000
Microsoft has released a patch and a tool that eliminate a security vulnerability in Microsoft(r) Windows(r) 2000. The vulnerability could make it easier for a malicious user who had complete control over a Windows 2000 machine to compromise users' sensitive information.
Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-032.asp
A Protected Store is provided as part of CryptoAPI, in order to provide secure storage for sensitive information such as private keys and certificates. By design, the Protected Store should always encrypt the information using the strongest cryptography available on the machine. However, the Windows 2000 implementation uses 40-bit key to encrypt the Protected Store, even if stronger cryptography is installed on the machine.
This vulnerability weakens the protection on the Protected Store, but does not eliminate it. An attacker would need to gain complete administrative control over the machine that houses the Protected Store in order to gain access to it, and even then would still need to mount a brute-force cryptographic attack against it. However, customers who follow the recommended remediation for this vulnerability can ensure that such an attack would be significantly more difficult, if not impossible.
The patch package to eliminate this vulnerability contains a new version of PBASE.DLL, the module that provides the Protected Store functionality, and a tool named Keymigrt.exe. Installing PBASE.DLL will ensure that all future additions to the Protected Store are encrypted using the strongest cryptography available on the machine. However, the Keymigrt tool also needs to be run, in order to re-encrypt all items currently in the Protected Store. We recommend that system administrators place the Keymigrt tool into users' logon scripts to ensure that the tool is run the next time they log on.
Note: The patch package contains a patch that needs to be applied to all affected machines, and a tool that should be run on all affected machines. The FAQ and Knowledge Base article provide additional details on their use.
Note: Additional security patches are available at the Microsoft Download Center
Please see the following references for more information related to this issue. - Frequently Asked Questions: Microsoft Security Bulletin MS00-032, http://www.microsoft.com/technet/security/bulletin/fq00-032.asp - Microsoft Knowledge Base article Q260219 discusses this issue and will be available soon. - Microsoft TechNet Security web site, http://www.microsoft.com/technet/security/default.asp
This is a fully supported patch. Information on contacting Microsoft Technical Support is available at http://support.microsoft.com/support/contact/default.asp.
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Last updated June 01, 2000