BigPond 3G21WB Hardcoded Credentials / Command Injection

`Hard-coded credentials and command-injection vulnerabilities on BigPond 3G21WB  
==============================================================================  
  
[ADVISORY INFORMATION]  
Title: Hard-coded credentials and command-injection vulnerabilities   
on BigPond 3G21WB  
Discovery date: 17/09/2012  
Release date: 11/10/2012  
Credits: Roberto Paleari ([email protected], @rpaleari)  
  
[VULNERABILITY INFORMATION]  
Class: Authentication bypass, command-injection  
  
[AFFECTED PRODUCTS]  
We confirm the following device models to be affected:  
* BigPond 3G21WB  
  
Similar routers are probably vulnerable to these very same issues.  
  
[VULNERABILITY DETAILS]  
The firmware running on the affected routers is subject to multiple security  
issues that allow an unauthenticated attacker to gain administrative access to  
the device and execute arbitrary commands. In the following paragraphs we  
describe the details of the vulnerabilities we identified.  
  
a) Hard-coded credentials  
A user can authenticate to the web server running on the device using the  
credentials "Monitor:bigpond1". These credentials are hard-coded, and cannot  
be changed by a normal user.  
  
b) Command-injection vulnerability  
The "ping.cgi" web page is subject to a command-injection vulnerability, as  
the server-side script does not properly validate user-supplied input.  
  
The following URL exploits this issue, executing the "ls /" command:  
http://<device IP address>/ping.cgi?DIA_IPADDRESS=;%20cat%20/etc/passwd  
  
[REMEDIATION]  
We are not aware of an updated firmware that corrects the issues described in  
this advisory. We suggest users to disable web access on the WAN side.  
  
[DISCLOSURE TIME-LINE]  
* 17/09/2012 - Initial vendor contact.  
  
* 18/09/2012 - Vendor replied asking for details.  
  
* 19/09/2012 - The author replied and asked for a technical  
contact. Disclosure date set to October 10th, 2012 (3  
weeks).  
  
* 19/09/2012 - Vendor replied, providing the phone contact number of the  
Technical Support Department.  
  
* 20/09/2012 - The author replied, asking to keep all the communication  
through e-mail, in order to keep track of the whole  
conversation.  
  
* 24/09/2012 - No response from the vendor. The author re-sent the last  
e-mail.  
  
* 04/10/2012 - No response from the vendor. The author re-sent the last  
e-mail (again).  
  
* 11/10/2012 - Still no response from the vendor. Disclosure.  
  
[DISCLAIMER]  
The author is not responsible for the misuse of the information provided in  
this security advisory. The advisory is a service to the professional security  
community. There are NO WARRANTIES with regard to this information. Any  
application or distribution of this information constitutes acceptance AS IS,  
at the user's own risk. This information is subject to change without notice.  
`