CAPEC 5

This attack against older telephone switches and trunks has been around for decades. The signal is sent by the attacker to impersonate a supervisor signal. This has the effect of rerouting or usurping command of the line and call. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded telco infrastructure and so are vulnerable to Blue boxing.

Blue boxing is a result of failure on the part of the system to enforce strong authentication for administrative functions. While the infrastructure is different than standard current applications like web applications, there are hisotrical lessons to be learned to upgrade the access control for administrative functions.

Attacker identifies a vulnerable CCITT-5 phone line, and sends a combination tone to the switch in order to request administrative access. Based on tone and timing parameters the request is verified for access to the switch. Once the attacker has gained control of the switch launching calls, routing calls, and a whole host of opportunities are available.