Australia’s second biggest telco, Optus, has launched a new automated SMS scam-blocking service, utilising intelligence supplied by the Australian Financial Crimes Exchange (AFCX).

The service, known as ‘Call Stop’, is designed to prevent Optus customers from falling prey to ‘call back’ scams by blocking customers’ attempts to call pre-identified scam numbers.

Customers are not only prevented from phoning scammers, but are also forwarded to an automated message to warn them that they have encountered a scam.

“[The service provides] a clear indication that the warning or threat received was indeed a fake scam message and no action is needed,” Optus said in a statement.

Call back scams are a type of social engineering fraud whereby consumers receive a fraudulent email or SMS (typically notifying them of concerns with their bank account) that directs them to call back their bank on a phone number provided – a number that ultimately directs them to a scammer impersonating their bank.

Scammers then trick the victim into providing access to their account or transferring their money into an account controlled by the scammer.

Call Stop makes use of a phone number blacklist created by the AFCX, which is generated from scam reports provided by banks and customers.

“Call and Text scams are the cause of significant financial loss and emotional distress to many Australians,” said ACFX managing director David Pegley. “These types of scams are on the rise in 2023, and criminals are using more and more sophisticated methods to catch people out.

“Our collaboration with Optus, with the support of our banking members, uses innovative technology to better protect consumers being targeted by scammers. It’s hoped that initiatives like Call Stop will curb the acceleration of this scamming technique.”

The AFCX is an independent, not-for-profit financial crimes investigation and prevention organisation. Though founded and funded by the big four banks (CBA, Westpac, ANZ, and NAB), the AFCX operates independently of its members.

Commenting on the launch of Call Stop, Australian Banking Association (ABA) deputy chief executive Vanessa Beggs said the new service illustrates the necessity of cross-industry collaboration to effectively halt scammers.

“With most scams starting with an SMS or phone call, this approach highlights why we need telcos to take down these scam numbers so they can’t be used to trick more consumers,” Beggs said.

She added: “ABA will work with its members to contribute to this initiative and encourages others in the telecommunication industry to also take part.”

Earlier this year, CBA and Telstra released details on a proof-of-concept for their Scam Indicator service, a co-developed solution which uses artificial intelligence to detect, in real time, whether a customer is potentially on a phone call with a scammer.

The bank can then warn customers of the likely scam or “put in additional checks” that prevent customers from transferring money to a scammer.

Last year, Australians lost more than $3 billion to scammers, according to the ACCC’s Scamwatch service, an 80 per cent increase on total losses recorded in 2021.

The ACCC flagged “significant gaps between and within” the banking, telecommunications and digital platforms sectors’ scam prevention efforts, particularly in coordinating their anti-scam activities.

“[We] would like to see initiatives that apply across the sectors, knowing that scammers will target the weakest link,” adding that the wider industry needs to “stop scammers reaching consumers by disrupting phone calls, SMS, email, social media messaging or other ways in which scammers contact would-be victims”.

Telcos also have an outsized role in blocking scams facilitated through their networks, with the recent introduction of Federal regulations showing how effective their efforts can be.

The introduction of the ACMA-mandated Reducing Scam Calls and SMS Code in 2022, which requires telecommunications providers to actively monitor and block scam calls, coincided with a 55.9 per cent decrease in phone scams between 2021 to 2022 – from 144,603 scam reports to 63,821, respectively.