Swatting, for those not familiar with the term, refers to the practice where bored or otherwise malicious users call 911 and target a certain address, attempting to place a call so dire that a SWAT team must be called out. Targets of a swatting prank can be anyone from celebrities to those who have somehow offended bored teenagers. But with caller ID so prevalent, how can anyone perpetrate such an act without having its consequences land directly on the perpetrator's own head?

The good news, for those who operate the 911 system in the United States, is that commonly there aren't holes in the system or similar vulnerabilities that need to be patched or otherwise addressed at the operator level. The whole thing can be traced back, essentially, to those engaging in swatting "fooling the system," as reports describe, from their own place of operations.

Referred to as "caller ID spoofing," it requires a marginal amount of control over the network since the phone itself doesn't transmit the caller ID signal. Outbound caller ID can't be sent over an analog plain old telephone service (POTS) signal either. Sending custom caller ID from a device, therefore, requires either a basic rate interface augmented by a D channel, or a full primary rate interface.

That's out of the range of most bored teenagers, so most then turn to services like Spoofcard, which allow users to make a call from a home phone or the like to an access number, which then allows those users to make a call to the desired destination number. This is at least somewhat similar to a proxy service for computers, as Spoofcard and the like are managed online, allowing a user to display whatever phone number he or she would like instead of the actual number. While that would seem to be the end of it, it's actually quite simple for investigating entities like the FBI to get access to the original number on the Spoofcard service.

Those using voice over Internet Protocol services (VoIP), have a similar ability to provide their own outbound number, but even here there is a "breadcrumb" trail of sorts that leads back to the original caller, Others have tried making calls from telecommunications devices for the deaf (TDD) systems that offer physical-level protections for pranksters, but even here the number can be physically traced.

Many of the common hacking methods, in fact, are being rendered useless the farther along things go, and in many cases calls can even be traced after the call was completed, making many hacking attempts ultimately fruitless. Indeed, the LAPD recently changed its stance on swatting calls, no longer publicizing them as it would have in the past and turning the perpetrators into--at least temporary--celebrities themselves.

Basically, swatting is a problem. It's the kind of thing that might well get people killed, and the wrong people at that. Not only is there risk to the victim of the swatting call, the person whose house police were sent to, but also to the police and to others who may have actually needed help. Thankfully, more and more measures to counter swatting are coming into play, making swatting a prank not only dangerous to its targets, but to its practitioners as well.