Microsoft Security Bulletin (MS00-087)
Patch Available for "Terminal Server Login Buffer Overflow"
Originally posted: November 08, 2000
Microsoft has released a patch that eliminates a security
vulnerability in Microsoft(r) Windows NT 4.0 Terminal Server. The
vulnerability could allow a malicious user to cause the Terminal
Server to fail or, in certain instances, to execute hostile code on
Frequently asked questions regarding this vulnerability and the patch
can be found at
An unchecked buffer in the Terminal Server login prompt could allow a
malicious user to cause the Terminal Server to execute arbitrary
code. The ability to execute arbitrary code would enable the
malicious user to add, change, or delete data, run code already on
the server, or upload new code to the server and run it. The
malicious user would not need to successfully login to the Terminal
Server in order to initiate this attack.
This vulnerability could be exploited remotely if connection requests
are not filtered. By default, Terminal Server listens on tcp port
3389. This port should be blocked at the firewall and/or router if
Terminal Server access from the Internet is not required.
Affected Software Versions
- Microsoft Windows NT 4.0 Terminal Server
- Microsoft Windows NT 4.0 Terminal Server:
Note: Additional security patches are available at the Microsoft
Please see the following references for more information related to
- Frequently Asked Questions: Microsoft Security Bulletin MS00-087
- Microsoft Knowledge Base article Q277910 discusses this issue
and will be available soon.
- Microsoft TechNet Security web site,
Obtaining Support on this Issue
This is a fully supported patch. Information on contacting Microsoft
Product Support Services is available at
Microsoft thanks Bruno Acselrad of CORE SDI (www.core-sdi.com) for
reporting this issue to us and working with us to protect customers.
November 08, 2000: Bulletin Created.
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Last Updated November 08, 2000