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.