Hacking VoIP

Anonymous Eavesdropping and Call Redirection

Man-in-the-middle attacks have plagued networks for many years. Tools from Dsniff/fragrouter to Cain & Abel help show how network communication methods are not secure. Using the same model, telephone communication via VoIP can fall into the same problem space. While Layer 2 man-in-the-middle attacks using ARP packets are by far the easiest way to eavesdrop on a call, access to the correct network space is required. Unfortunately, there are a few ways to eavesdrop without using ARP poisoning—using common phishing attacks in combination with call redirection.

The first kind of this attack is a targeted attack, involving Caller ID spoofing. The attacker essentially creates a three-way call between the credit ...