Allied Telesis AT-RG634A ADSL Broadband Router - 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/