Vulnerability Note VU#500027

3Com HomeConnect Cable Modem vulnerable to DoS via long string of characters

Overview

Intruders can disrupt the normal operation of a 3Com HomeConnect Cable Modem.

I. Description

The 3Com HomeConnect Cable Modem contains a web server. This web server is used to administer the cable modem. By default, this web server is configured to allow any user (local or remote) to connect to 80/tcp.

II. Impact

If an intruder connects to the web server and issues a specially crafted GET request, the cable modem will reset. When the modem resets, it will lose all of it's network configuration information along with any other configuration data. Until this data is restored, the hosts on the internal side of the cable modem will have no connectivity to the outside network.

III. Solution

The CERT/CC is currently unaware of a practical solution to this problem.

Workaround
Configure the cable modem to filter 80/tcp.

Systems Affected

Vendor	Status	Date Updated
3Com	Unknown	27-Dec-2001

References

http://www.securityfocus.com/bid/3366

Credit

The CERT/CC thanks Alex S. Harasic for reporting this vulnerability.

This document was written by Ian A. Finlay.

Other Information

Date Public	09/26/2001
Date First Published	12/27/2001 01:30:43 PM
Date Last Updated	04/09/2003
CERT Advisory
CVE Name	CAN-2001-1293
US-CERT Technical Alerts
Metric	7.50
Document Revision	18

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