Allied Telesis AT-RG634A Unauthenticated Webshell

                							

                *Title:*
 
Allied Telesis AT-RG634A ADSL Broadband router hidden administrative
unauthenticated webshell.
 
*Vulnerability Information:*
- CVE: CVE-2014-1982
- Type of Vulnerability:
  - CWE-78  : OS Command Injection
  - CWE-306 : Missing Authentication for Critical Function
 
*Affected products:*
 
- Allied Telesis AT-RG634A ADSL Broadband router. (version 3.3+ and
probably others)
 
Other products like,
   - Allied Telesis iMG624A  (firmware version, 3.5)
   - Allied Telesis iMG616LH (firmware version, +2.4)
   - Allied Telesis iMG646BD (firmware version, 3.5)
 
*Vendor:*
- Allied Telesis : http://www.alliedtelesis.com//
 
 
has the same vulnerbility, but the vendor reports that the version
3.8.05 of the firmware has already addressed this issue, but we where
unable to test nor confirm this information.
 
*Security Patches / Workaround:*
 
- Allied Telesis has noted that the AT-RG634A product is no longer
supported, but gives a workaround
to mitigate the issue.
 
Configure the device so that only trusted devices can
access the target device using the following command,
 
"WEBSERVER SET MANAGEMENTIP <ip-address>"
 
*Short Description:*
 
The Allied Telesis AT-RG634A ADSL Broadband router has a hidden url
page in their admnistrative HTTP interface capable of executing
commands as admin without requiring any kind of authentication.
 
*Description:*
 
"The AT-RG634 is a full-featured, broadband media gateway and router
designed for cost-effective delivery of advanced IP Triple Play voice,
video and data services over an ADSL infrastructure. The RG634
supports Layer 3 functions, including NAT, DMZ, and Stateful
inspection firewall for delivery of revenue-generating services such
as home networking and security services." (from
www.alliedtelesis.com/p-2345.html)
 
The Allied Telesis AT-RG634A ADSL Broadband router has a hidden URL
(/cli.html) page to execute CLI command with admin priviledges,
available by default and without any kind of authentication.
 
Having as impact a total compromise of the target device.
 
*Steps to reproduce:*
 
- Connect via HTTP to the hidden page http://<device IP>/cli.html a
input box is shown, every command typed there will be executed as admin.
 
Entering the following lines in the hidden page (/cli.html) a new
telnet admin user called "eviluser" is added to the system.
 
>> system add login eviluser system set user eviluser access
>> superuser.
 
 
*Credits:*
 
This security issue was discovered and researched by Sebastian Muniz
(topo), Security Researcher of Groundworks Technologies
(http://www.groundworkstech.com)
 
 
*License:*
 
The contents of this advisory are copyright (c) 2014 Groundworks
Technologies,and are licensed under a Creative Commons Attribution
Non-Commercial Share-Alike 3.0 (United States) License:
http://creativecommons.org/licenses/by-nc-sa/3.0/us/


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