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/  
  
  
`