Telstra mobile customers can expect to receive fewer SMS-based scam messages after the company switched on a “complex and evolving” filter to combat the ‘smishing’ scams that have already cost Australians over $2m this year alone.

Smishing is the sending of fraudulent messages to trick the recipient into clicking on a malicious link.

The telco’s network-level smishing detection technology has proved itself during three months of internal testing by around 2,500 employees, now-departed Telstra CEO Andy Penn said in launching the new service – which has now been rolled out across all of Telstra’s 19.5m mobile services.

“We’ve been successful in detecting and blocking hundreds of scam SMS messages every day,” Penn said, noting that “the capability under the bonnet is complex and evolving – it has to be to continue to help outsmart scammers.”

Machine learning technology assesses messages against a range of factors including the presence of malicious links, the time and sender of the message, the number of messages sent, and the recipient.

“We know you have probably all experienced a fake parcel delivery text message or badly punctuated message about a video or unexpected payment,” Penn said. “Now, with Telstra’s SMS scam filter switched on, you’ll be receiving fewer annoying and risky messages.”

Suspicious messages may be flagged by the system and reviewed by human specialists, with details of the recipient masked to protect privacy.

The new smishing filter adds another prong to Telstra’s ongoing Cleaner Pipes initiative, which has previously seen the carrier deploying technology to block scam calls – Penn said Telstra blocked over 100 million scam calls over the past year alone – as well as filtering malicious websites at the DNS level and cracking down on SIM swapping fraud.

Yet “while we’re confident our SMS scam filter will block a significant amount of scam text messages, it isn’t fool-proof and criminals evolve and find new ways to scam us,” he wrote. “We’ve all got to continue to be alert to suspicious messages – even the ones that might slip through.”

Blocking threats upstream

By filtering malicious content well before it even reaches users, Telstra is aiming to not only save its customers from inadvertently clicking on malware links but to stop them incurring financial losses from determined scammers.

Australians reported 14,786 scam text messages in the first two months of this year alone, according to the ACCC’s ScamWatch service – making SMS scams by far the most frequently-reported form of scam.

And while overall losses to text-message scams are lower than those lost through other channels – $2.43m this year, compared with $21.7m lost to phone scammers – the volume of scams is already up significantly from 2021, when Australians reported losing $10.1m to 67,180 SMS scams for the entire year.

Telstra’s scam filtering service appears to be setting the pace for a practice that is gaining currency around the world as smishing volumes soar.

A recent RoboKiller report estimated that US residents alone were targeted with 87.8 billion spam text messages and 72.2b scam phone calls during 2021 – up 58 per cent and 32 per cent, respectively, from the previous year.

RoboKiller’s paid monthly service not only identifies scam calls, but answers the calls and engages the ‘robodialers’ to tie them up for as long as possible.

It’s one of the myriad solutions available independently and through US mobile carriers such as T-Mobile, whose free Scam Shield app vets incoming messages and calls, and checks them against a list of known scam originators.

Singapore’s government offers a similar service, also called ScamShield, that lets residents block calls from a database of blocked numbers maintained by that country’s National Crime Prevention Council and Singapore Police Force.

French presidential candidate Emmanuel Macron has even floated a universal anti-scam filter as part of his re-election platform – promising to introduce a DNS filter that would intercept visits to known fraudulent websites, then warn users in real time and assist them with a phone support line and force of 1,500 ‘cyber patrollers’.

Such services work well at the user end, but Telstra’s network-level filtering remains an aspirational target for many industry players – with Nomorobo founder Aaron Foss testifying to US Congressional hearings that “putting more pressure on carriers to put this in natively… will be ultimately what solves the problem.”