Carrier billing security company Upstream reported a significant number of fraudulent transaction attempts in 2019, blaming malware-infected Android devices and rogue adverts as the primary factors.

Data covering 31 operators from 20 countries showed Upstream’s Secure-D platform, which identifies and blocks fraudulent mobile transactions, prohibited 1.6 billion of the 1.71 billion transactions the service handled in 2019.

The company estimated if these transactions were left unchecked, they would have resulted in unwanted charges of $2.1 billion for mobile users.

Upstream said 43 million Android devices were infected by 98,000 malicious apps in 2019, up from 63,000 in 2018.

CEO Dimitris Maniatis warned mobile ad fraud greatly affected the whole mobile ecosystem, noting an adverse impact on consumers by “eating up their data allowance, bringing unwanted charges, messing with the performance of their device, and even targeting and collecting their personal data”.

“It is more than an invisible threat, it is an epidemic, calling for increased mobile security that urgently needs to rise up in the industry’s priority list.”

Upstream noted emerging markets were highly affected by mobile ad fraud, with Brazil and South Africa being among the most impacted, with fraud rates of more than 90 per cent of mobile transactions processed.