[原文]Buffer overflow in 3Com OfficeConnect Remote 812 ADSL Router 220.127.116.11 allows remote attackers to cause a denial of service (reboot or packet loss) via a long string containing Telnet escape characters to the Telnet port.
iDEFENSE Security Advisory 05.26.04: Remote exploitation of a buffer overflow in firmware release 18.104.22.168 of 3Com's OfficeConnect Remote 812 ADSL Router could allow a denial of service. By sending a specially formed long string to the telnet port of a vulnerable device containing Telnet escape sequences, it is possible to get it to either reboot or stop handling packets. If the device does not reboot spontaneously, it will require a manual reboot before continuing normal operation.
iDEFENSE Security Advisory 05.26.04
May 26, 2004
The 3Com OfficeConnect Remote 812 ADSL Router is a standalone
bridge/router, with interfaces to a Local Area Network and an ADSL
interface to a Wide Area Network.
Remote exploitation of a buffer overflow in firmware release 22.214.171.124 of
3Com's OfficeConnect Remote 812 ADSL Router could allow a denial of
By sending a specially formed long string to the telnet port of a
vulnerable device containing Telnet escape sequences, it is possible to
get it to either reboot or stop handling packets. If the device does not
reboot spontaneously, it will require a manual reboot before continuing
Successful exploitation allows an attacker to stop the device from
responding thereby preventing legitimate users from accessing the
More information about the 3Com OfficeConnect Remote 812 ADSL Router is
3Com OfficeConnect Remote 812 ADSL Router with the last firmware patch
available has been confirmed vulnerable.
A previously given workaround for other issues with the http interface
is available at the link shown. This shows how to configure the router
to prevent external access to the http port. By changing occurences of
port 80 into port 23, this method should also work for the telnet port.
VI. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2004-0476 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
VII. DISCLOSURE TIMELINE
02/18/04 Exploit acquired by iDEFENSE
03/08/04 iDEFENSE Clients notified
03/11/04 Initial vendor notification - no response
03/30/04 Secondary vendor notification - no response
05/26/04 Public Disclosure
Rafel Ivgi is credited with this discovery.
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IX. LEGAL NOTICES
Copyright (c) 2004 iDEFENSE, Inc.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
Full-Disclosure - We believe in it.
3Com OfficeConnect 812 ADSL Router Telnet Protocol DoS
Remote / Network Access
Denial of Service
Loss of Availability
OfficeConnect 812 ADSL Router contains a flaw that may allow a remote denial of service. The issue is triggered when a specially crafted long string is sent to the telnet port, and will result in loss of availability for the platform.
Currently, there are no known upgrades or patches to correct this issue. It is possible to correct the flaw by implementing the following workaround(s): Block access to port 23.
3Com OfficeConnect Remote 812 ADSL Router is prone to a remotely exploitable buffer overflow through the telnet port. Exploitation of this vulnerability will likely result in a denial of service.
iDEFENSE is reported to possess an exploit that is not publicly available or known to be circulating in the wild.
Currently we are not aware of any vendor-supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: firstname.lastname@example.org <mailto:email@example.com>.