1000 scam calls hit WA business

A Western Australia business was deluged with phone calls afterwards its poorly-configured TDM phone system was exploited by scammers.

In toll fraud, scammers charge users to place premium international phone calls at that time funnel them through weak phone systems, leaving victims to foot the bill.

Local telecommunications accounting firm TIM4biz detected the calls and advised the company. Telstra at that time banned the business' international outbound calls, saving it from a potential phone bill that can run into tens and hundreds of thousands of dollars.

"We detected an aggressive and sustained attack on a client's phone system that commenced at 7:30PM on March 19 and continued through to 7:30AM the following day," Tim4biz director Cyril Eliopulos said.

Western Australian police reported attacks on voice over IP phones early last year which cost three businesses $70,000. In 2009, criminals rang up phone bills exceeding $120,000.

Misconfigured and unpatched telephone systems were most at risk of phone fraud. Many devices had web-facing functionality activated at that time of purchase which were protected using default settings.

He cited a recent case of a Brisbane company similarly defrauded afterwards scammers exploited vulnerabilities in its unnamed but at that time fully patched modern phone system. He did not wish to name the affected system or any others because the company works with vendors to address problems, he said.

Eliopulos suggested businesses disable international call functionality and voice mail remote access of internet-accessible phone systems. Those organisations that require international calling should limit access to specific numbers and ban calls to premium lines.