Australia’s media watchdog fined Optus Mobile AUD826,320 ($535,988) for failing to comply with anti-scam rules, leading to financial losses and identity theft for some customers, as the agency steps up efforts to disrupt mobile number fraud.

An Australian Communications and Media Authority (ACMA) investigation found scammers exploited a vulnerability in a third-party identity verification system used by Optus, operating as Coles Mobile, enabling them to bypass parts of the required verification process.

The scammers gained control of at least four consumers’ mobile services and access their bank accounts, resulting in losses of AUD39,000.

ACMA member Samantha Yorke said while the vulnerability was a one-off issue, which was quickly remediated, “it is inexcusable for any telco not to have robust customer ID verification systems in place”.

She added the fine is the maximum financial penalty the ACMA was able to impose, reflecting the serious nature of the breaches.

Businesses have paid more than AUD1.9 million for breaches of the rules over the last 12 months.

Last month ACMA introduced new rules requiring organisations to register branded identifiers with their mobile operator in a crackdown on scammers using text messages to impersonate brands.