The Telecommunications Industry Group (TIG) has reported that fraud increased fourfold in 2010 with an estimated 30 to 40 New Zealand companies getting hit by international PABX fraudsters every month.

The group believes that it’s the small business that’s at most risk.

“An unsecured PABX system can be compromised via an insecure voicemail system, that allows incoming callers to dial extensions directly,” it said in a statement.

“From there, some insecure PABX systems can even allow callers to access outside lines. Hackers have targeted these systems around the world sometimes resulting in a large volume of international calls being charged to the PABX user’s account.”

The Telecommunications Industry Group has posted a set of guidelines to help secure your PABX system.