OZtell investigating security breach

Australian internet telephone provider OZtell is investigating a security breach following claims by users that their accounts were hacked and used to make expensive overseas calls.

Several users have taken to online forums to complain about breaches of accounts held with PennyTel and MaxoTel, two voice over internet protocol (VoIP) providers, which they used via OZtell's "Web Dialler".

They complained that their accounts were charged $15-20 for numerous calls to a mobile phone number in Morocco.

The Web Dialler is a controller for internet phone calls that lets users choose from a number of third-party telco providers to secure cheap rates.

It is not yet clear which company's security defences had been breached and investigations are ongoing, says OZtell in a post on its customer support forum.

"Whether the source of the leak is OZtell or not, we need to undo the damage so far and prevent further damage as much and as soon as possible."

Although the number of people affected appears low, "we have to assume the worst case for now", the post says.

OZtell says it has emailed customers who use the Web Dialler to access third-party VoIP providers encouraging them to delete their external accounts and to change their passwords.

It is also encouraging victims to report their call records in a bid to get a fuller picture of the incident, and says it will refund victims who are refused restitution by their VoIP providers.

OZtell did not respond to emails.