Microsoft Security Bulletin MS00-017

DOS device names are reserved words, and cannot be used as folder or file names. When parsing a reference to a file or folder, Windows correctly checks for the case in which a single DOS device name is used in the path, and treats it as invalid. However, it does not check for the case in which the path includes multiple DOS device names. When Windows attempts to interpret the device name as a file resource, it performs an illegal resource access that usually results in a crash.

Because it is not possible to create files or folders that contain DOS device names, it would be unusual for a user to try to access one under normal circumstances. The chief threat posed by this vulnerability is that a malicious user could attempt to entice a user to attempt such an access. For instance, if a web site operator hosted a hyperlink that referenced such a path, clicking the link would result in the user's machine crashing. Likewise, a web page or HTML mail that specified a local file as the source of rendering information could cause the user's machine to crash when it was displayed. If this happened, the machine could be put back into normal service by restarting it.

Affected Software Versions

• Microsoft Windows 95
• Microsoft Windows 98
• Microsoft Windows 98 Second Edition

Vulnerability Identifier: CVE-2000-0168

• Windows 95:

  http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=C041729D-BDE4-4E61-9364-4D02B9A78C5B

• Windows 98 and Windows 98 Second Edition:

  http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=4C6FD7E5-A66E-4A08-B782-2A64C77B95B6

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

  NOTE: The patch will be available shortly at the Windows Update site. When this happens, we will modify the bulletin to provide additional information.