Researchers from Secure-D, the mobile ad fraud division of UK-based mobile monetization firm Upstream, detailed their findings in a post published on Monday.

They discovered that VidMate has a hidden component within the app that delivers hidden ads, generates fake clicks and purchases, installs malicious apps and siphons off users' private information - all without their knowledge.

As a result, it eats up users' data allowance and costs them money.

Upstream researchers blocked over 128 million malicious mobile transactions that were attempted by the VidMate app on 4.8 million devices.

Had they not been blocked, they could have cost users a boatload of unwanted charges.