Vulnerability Note VU#568073

Canon digital multifunction copiers FTP bounce vulnerability

Overview

Some models of Canon digital multifunction copiers are vulnerable to the FTP bounce attack.

I. Description

From the Problems With The FTP PORT Commanddocument:

The FTP Bounce Attack

To conform with the FTP protocol, the PORT command has the originating machine specify an arbitrary destination machine and port for the data connection. However, this behavior also means that an attacker can open a connection to a port of the attacker's choosing on a machine that may not be the originating client.

Some Canon digital multifunction printers contain an FTP server that is vulnerable to the FTP bounce attack.

II. Impact

A remote, unauthenticated attacker may be able to conduct port scans or send arbitrary (TCP) traffic to other hosts.

III. Solution

We are currently unaware of a practical solution to this problem.

The following workarounds may mitigate this vulnerability.

Disable the affected FTP server
Administrators and users should either turn off the vulnerable FTP server or disable anonymous access. See the Steps to take to clear vulnerabilitysection of the Canon Web Advisory: Digital multifunction printer vulnerability for more information.

Use host based firewalls
Administrators and users can use host-based firewalls to prevent affected printers and other devices from creating connections to arbitrary TCP ports.

Systems Affected

Vendor	Status	Date Updated
Canon	Vulnerable	4-Mar-2008

References

http://www.usa.canon.com/html/security/pdf/CVA-001.pdf
http://www.canon-europe.com/For_work/Canon_Europe_CBS_Web_Advisory_Digital_Multifunction_Printers.asp
http://www.cert.org/tech_tips/ftp_port_attacks.html#3.2
http://nmap.org/hobbit.ftpbounce.txt

Credit

Thanks to Canon for information that was used in this report. Canon credits Nate Johnson and the Indiana University for reporting this vulnerability.

This document was written by Ryan Giobbi.

Other Information

Date Public	02/28/2008
Date First Published	02/28/2008 02:46:21 PM
Date Last Updated	03/04/2008
CERT Advisory
CVE Name	CVE-2008-0303
US-CERT Technical Alerts
Metric	0.72
Document Revision	11