NETGEAR CG814WG Cross Site Request Forgery

Type packetstorm
Modified 2011-09-21T00:00:00


                                            `Sense of Security - Security Advisory - SOS-11-011  
Release Date. 20-Sep-2011  
Last Update. -  
Vendor Notification Date. 22-Mar-2011  
Product. NETGEAR Wireless Cable Modem Gateway  
Affected versions. Hardware 1.03,   
Software V3.9.26 R14 verified,  
possibly others  
Severity Rating. High  
Impact. Authentication bypass,  
Cross Site Request Forgery  
Attack Vector. Remote without authentication  
Solution Status. Upgrade to R15 (by contacting NETGEAR)  
CVE reference. Not yet assigned  
The NETGEAR Wireless Cable Modem Gateway CG814WG is supplied by ISP's   
as customer premises equipment within Australia and abroad. It is a   
centrally managed ISP solution whereby each ISP's devices run a   
customised firmware and configuration changes and updates can be pushed   
out as required.   
Basic authentication is used as the primary and only authentication   
mechanism for the administrator interface on the device. The basic   
authentication can be bypassed by sending a valid POST request to the   
device without sending any authentication header. The response from the   
device sends the user to another page that requests basic   
authentication, however at this point the request has already been   
An example of attacks using the basic authentication bypass may include   
changing the admin password or enabling the remote admin interface   
(Internet facing).   
Additionally, due to the lack of CSRF protection in the web application,   
the bypass attack can be coupled with CSRF to have a victim enable the   
remote admin interface to the Internet, where an attacker can then use   
the bypass attack again across the remote admin interface to reset the   
admin password and access the device. This attack is possible when   
targeting a victim that is behind the NETGEAR device on the same segment   
as the web administrator interface whom has browsed to a malicious site   
containing the CSRF attack.   
NETGEAR was notified of this vulnerability on 22 March 2011, but we   
never received a response or acknowledgement of the issue or fix. Sense   
of Security notified local ISP's and it was escalated by a local ISP   
who worked with NETGEAR to develop and test an update. Sense of Security   
was never provided an opportunity to validate the fixes in the latest   
firmware version. Given the severity of the issue it would be prudent   
for NETGEAR to notify and supply an update to all of its customers.   
Proof of Concept.   
By embedding the below HTML in a website and having a   
victim browse to the website the remote management interface to the   
Internet would be enabled. An attacker could then use one of the   
hardcoded passwords for the device to access it, or use a basic   
authentication bypass to change the admin password. Alternatively, the   
attacker could conduct a CSRF attack that implements two POST requests   
to have the remote admin interface enabled, and the admin password   
The example here is a basic proof of concept, more complex examples   
which include JavaScript redirects to mask the basic authentication   
pop-up would be more stealthy.   
<body onLoad=javascript:document.form.submit()>  
<form action=""  
method="POST" name="form">  
<input type="hidden" name="NetgearRmEnable" value="0x01">  
<input type="hidden" name="NetgearRmPortNumber" value="1337">  
<input type="hidden" name="NetgearUserLevel" value="1">  
Ask your ISP to obtain the latest firmware from NETGEAR and deploy it  
to your device.  
Discovered by.  
Sense of Security Labs.  
About us.  
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skills in assessment and assurance, strategy and architecture,  
and deployment through to ongoing management. We are  
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Sense of Security Pty Ltd   
Level 8, 66 King St  
Sydney NSW 2000  
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