Microsoft Security Bulletin MS00-020 - Critical
Patch Available for "Desktop Separation" Vulnerability
Published: June 15, 2000
Originally Posted: June 15, 2000
Microsoft has released a patch that eliminates a security vulnerability in Microsoft® Windows® 2000. The vulnerability could allow a malicious user to gain additional privileges on a machine that he could log onto at the keyboard.
Frequently asked questions regarding this vulnerability can be found at https://www.microsoft.com/technet/security/bulletin/fq00-020.mspx.
In the Windows 2000 security model, a hierarchy of container objects is used to separate processes. Every session contains one or more windows stations; every windows station contains one or more desktops. By design, processes are constrained to run within a windows station, and the threads in the process run in one or more desktops. A process in one windows station should not be able to access desktops belonging to another windows station. However, due to an implementation error, this could happen under very specific circumstances. This could allow a process belonging to a low-privilege user to view inputs or output that belong to another desktop within the same session, and potentially obtain information such as passwords.
The vulnerability only affects desktops within the same session. As a result, a malicious user could only interfere with processes on the same local machine, and only if he could interactively log onto it. Security best practices strongly militate against allowing normal users to interactively log onto security-sensitive servers, and if this practice has been followed, machines such as domain controllers, print and file servers, ERP servers, database servers, and others would not be at risk. In addition, other security best practices, if followed, would prevent a malicious user from launching the processes in a way that allows them to exploit this vulnerability. Windows 2000 Terminal Servers are not affected by this vulnerability, because every user runs in his own session.
Affected Software Versions
- Microsoft Windows 2000 Professional
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Advanced Server
Vulnerability Identifier: CVE-2000-0475
Note: Due to a known compatibility error, the patch should not be applied to clustered Windows 2000 systems that are administered via the Microsoft Management Console.
Note: Additional security patches are available at the Microsoft Download Center
Please see the following references for more information related to this issue.
- Microsoft Security Bulletin MS00-020: Frequently Asked Questions
- Microsoft Knowledge Base (KB) article 260197, Interactive Logon may Allow Desktop Process Privilege Elevation
- Microsoft TechNet Security web site.
Obtaining Support on this Issue
This is a fully supported patch. Information on contacting Microsoft Technical Support is available at https:
- June 15, 2000: Bulletin Created.
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