Vulnerability Note VU#570330

MS Windows NT Terminal Server 4.0 buffer overflow in regapi.dll allows remote code execution or DoS

Overview

Microsoft Windows NT 4.0 Terminal Server contains a buffer overflow that could allow an intruder to execute arbitrary code with the privileges of an administrator.

I. Description

There is a buffer overflow in the code that processes the username (specifically in RegAPI.DLL) in Microsoft Windows NT 4.0 Terminal Server. This allows an intruder to submit a specially crafted username in such a way as to cause Terminal Server to execute code of the intruder's choosing. The intruder does not need to have a valid username or password; anyone with access to port 3389/TCP can exploit this vulnerability.

II. Impact

Intruders can execute arbitrary code with the privileges of a logged in administrator. Additionally, an intruder who can log in locally can cause Terminal Server to crash.

III. Solution

Apply a patch as described in http://www.microsoft.com/ntserver/terminalserver/downloads/critical/q277910/default.asp.

You may also with to block access to port 3389/TCP to reduce your exposure to this vulnerability. This does not eliminate the vulnerability, but it does reduce the number of people who can exploit it.

Systems Affected

Vendor	Status	Date Updated
Microsoft	Vulnerable	15-Aug-2001

References

http://www.securityfocus.com/bid/1924
http://www.microsoft.com/technet/security/bulletin/ms00-087.asp
http://www.microsoft.com/technet/security/bulletin/fq00-087.asp

Credit

This vulnerability was discovered by Bruno Acselrad of CORE SDI S.A., Buenos Aires, Argentina.

This document was written by Shawn V. Hernan.

Other Information

Date Public	11/08/2000
Date First Published	08/15/2001 12:29:52 AM
Date Last Updated	08/15/2001
CERT Advisory
CVE-ID(s)	CAN-2000-1149
NVD-ID(s)	CAN-2000-1149
US-CERT Technical Alerts
Metric	16.87
Document Revision	5

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