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CA-2001-37 Buffer Overflow in UPnP Service On Microsoft Windows


CERT Advisory CA-2001-37 Buffer Overflow in UPnP Service On Microsoft Windows

Original release date: December 20, 2001
Last revised: --
Source: CERT/CC

A complete revision history can be found at the end of this file.

Systems Affected

* Microsoft Windows XP
* Microsoft Windows ME
* Microsoft Windows 98
* Microsoft Windows 98SE


Vulnerabilities in software included by default on Microsoft Windows
XP, and optionally on Windows ME and Windows 98, may allow an intruder
to execute arbitrary code on vulnerable systems, to launch
denial-of-service attacks against vulnerable systems, or to use
vulnerable systems to launch denial-of-service attacks against
third-party systems.

I. Description

There is a vulnerability in the Universal Plug and Play (UPnP) service
on Microsoft Windows XP and Microsoft Windows ME that could permit an
intruder to execute arbitrary code with administrative privileges on a
vulnerable system. The UPnP service is enabled by default on XP.
Microsoft does not ship Windows ME with UPnP enabled by default, but
some PC manufacturers do. UPnP may be optionally installed on Windows
98 and Windows 98SE. This vulnerability was discovered by Eeye Digital
Security. For more information, see

Universal Plug and Play (UPnP) is a set of protocols that allow
computer systems and network devices to work together with little or
no prior configuration.

One vulnerability is a buffer overflow in the code that handles UPnP
NOTIFY directives. This vulnerability permits an intruder to send a
malicious NOTIFY directive to a vulnerable computer and cause the
computer to run code of the intruder's choice. The code will run with
full privileges on all vulnerable systems, including Windows XP. This
can permit an attacker to take complete control of the system.

A second vulnerability in the Microsoft Windows implementation of UPnP
could allow an intruder to consume memory and processor time on
vulnerable systems, resulting in performance degradation. Variations
on this problem can allow an intruder to use a vulnerable system to
launch a denial-of-service attack against a third-party.

For more information about these vulnerabilities, see

These vulnerabilities have been assigned the CVE identifiers
CAN-2001-0876 and CAN-2001-0877, respectively.

II. Impact

Intruders can gain complete control of vulnerable systems, or
interrupt the normal operation of vulnerable systems.

III. Solution

Apply a patch from your vendor

Microsoft has provided patch information in their bulletin. Please see
MS01-059, available from

Block Access to UPnP Service

Until a patch can be applied, you can reduce your exposure to this
problem by blocking access to ports 1900 and 5000 at your network
border. This does not eliminate your exposure to attacks originating
from within your network, however.

Note that Microsoft Internet Connection Firewall, which runs by
default on Windows XP, does not provide complete protection against
this attack. Specifically, an intruder can still use a broadcast or
multicast address to reach the UPnP service on Microsoft Windows. On
systems that don't require UPnP, it can be disabled.

Author: Shawn V. Hernan

This document is available from:

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Copyright 2001 Carnegie Mellon University.

Revision History
December 20, 2001: Initial release

Version: PGP 6.5.8


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