Ransom Demand Probed After Data Hack, Australia’s Optus Says

Australian mobile-phone company Optus said authorities are investigating an online ransom demand following a major data hack that exposed the personal details of as many as 10 million customers.

The Singapore Telecommunications Ltd.-owned company is still trying to retrieve the data and is working with police and cybersecurity officials, Chief Executive Officer Kelly Bayer Rosmarin said Tuesday. The Australian Federal Police is “all over” an online post indicating that customer details will be sold unless Optus paid a ransom, she said.

So-called ransomware hacks have soared worldwide in recent years, with attackers targeting businesses, schools and even hospitals. Since ...