VoIP and Toll Fraud

I recently got to analyze some VoIP toll fraud and created an algorithm for detecting different types of fraud whether it was international or interlata calling.  The algorithm alerted on a couple of false positives, but overall has been an overwhelming success in combating the fraudulent behavior.  Today, we are mostly detecting when a customer's PBX gets compromised and can shut down the fraud quite quickly and notify the affected customer before they even notice that they were compromised.

Prior to implementing my detection algorithms, there could be $1,000s or even $10,000s racked up in fraudulent calls and the detection would occur about 8 to 10 hours after the fraud started.  Today, we're catching the fraud in most cases when the fraudster is placing their test calls to see if the credentials they obtained even work. It is always within the first hour of the fraud occurrence.

I'm sure that I'll need to extend my algorithms over time as the fraudsters change the signature of their attempts, but I'll take that as a challenge. It is much more pleasurable being on top of the fraud and squashing their every attempt.