In early 2009, HD Moore reinvented wardialing with the creation of WarVOX. Since then, penetration testers (and mischievous pranksters) have used it to call millions of phone numbers, looking for interesting devices plugged into phone lines. HD unveiled the next generation at BSides Las Vegas with WarVOX 2 -- a complete rewrite of WarVOX with new features and an eye toward full inclusion within Metasploit.

During his talk, the CSO of Rapid7 discussed the evolution of Metasploit since the project was released in 2003, as well as some of the highlights of the new 4.0 release. Next, HD debuted WarVOX 2, discussing some of the major problems with version 1 and its dependencies on various libraries. To deal with those issues, HD rewrote WarVOX and created a VoIP stack in Ruby -- a programming language -- so WarVOX would have native support to make calls without relying on unreliable third-party code libraries.

In addition to the new Ruby VoIP code and the complete code rewrite, HD moved WarVOX from SQLite3 to PostgreSQL (the same database commercially supported by Metasploit), so all voice recordings and images are stored in the database. A new audio fingerprinting system was created, and wardialing functionality has been added to Metasploit.

The move to Postgres makes sense because that's what Rapid7 officially supports for Metasploit, but where things get really interesting is the new audio fingerprinting. The fingerprinting is described as extremely CPU-intensive during the fingerprint creation process, but matching those fingerprints once generated is incredibly fast.

During the BSides talk, HD demonstrated the fingerprinting features by comparing recordings obtained by calling some of the Las Vegas hotels. He was able to quickly identify numbers where the same people had answered or recorded the voicemail greeting.

Practical purposes? Well, if you're doing recon for a penetration test and social engineering is within scope, imagine if you could call the voicemail of the employee, record his voice from his cell phone, and then call all the phone numbers at his office (or in the nearby residential area) and identify him automatically.

And, of course, there are all the juicy devices that have been plugged into phone lines, possibly for years, with poorly chosen passwords that allow you to bridge into the internal network or control systems remotely.

The WarVOX 2 code had been committed to the subversion software repository about two hours prior to HD's presentation, and phone scanning and audio recording functionality is now available in Metasploit, making it easy for anyone to be able to perform advanced wardialing. The question now is, how will you use it in your next penetration test?

John Sawyer is a Senior Security Analyst with InGuardians. The views and opinions expressed in this blog are his own and do not represent the views and opinions of his employer. He can be reached at [email protected]