Dangerous spyware masquerading as a set of legitimate Telegram “mods” inside the official Google Play app store has been downloaded tens of thousands of times — and its existence poses serious ramifications for business users.

Modified applications (“mods”) for the popular messaging client are a well-known part of the Telegram ecosystem. Mods are apps that have all the standard functionality of an official client, but they’re supercharged with extra features. In the case of Telegram, this kind of development is actively encouraged by the company and considered perfectly legitimate.