VoIP spam

VoIP spam, is the proliferation of unwanted, automatically-dialed, pre-recorded phone calls using Voice over Internet Protocol (VoIP). Some pundits have taken to referring to it as SPIT (for "Spam over Internet Telephony").

Voice over IP systems, like e-mail and other Internet applications, are susceptible to abuse by malicious parties who initiate unsolicited and unwanted communications. Telemarketers, prank callers, and other telephone system abusers are likely to target VoIP systems increasingly, particularly if VoIP tends to supplant conventional telephony.

The underlying technology driving this threat is SIP (Session Initiation Protocol, IETF – Internet Engineering Task Force, RFC 3261). This technology has received significant support from most major telecommunication vendors, and is showing signs of becoming the industry standard for voice, video and other interactive forms of communication such as instant messaging and gaming.

Similar rules to today’s email systems that block unsolicited email will also prevent unsolicited voice and video communication. This can also be compared to the way today’s chat applications prevent unwanted users from viewing your availability or state of presence by using “privacy” options.

SIP as the technology has been designed to support presence natively. This potentially means that incoming callers will know your availability before even attempting to call or make contact with you. So just like with e-mail today the benefits of communicating with trusted parties electronically far exceeds the pitfalls of e-mail spam, particularly when using preventative technologies to minimise the impact of the issue.

Resources

• Hansen, Markus; Hansen, Marit; Moeller, Jan; Rohwer, Thomas; Tolkmit, Carsten; Waack, Henning: "Developing a Legally Compliant Reachability Management System as a Countermeasure against SPIT", Third Annual VoIP Security Workshop, Berlin, June 2006.