WhatsApp users sometimes feel the official app is lacking a useful feature of one sort or another, be it animated themes, self-destructing messages which automatically delete themselves, the option of hiding certain conversations from the main list, automatic translation of messages, or the option of viewing messages that have been deleted by the sender. This is where amateurs step in with modified versions of WhatsApp which offer extra features.
These mods can contain ads, usually in the form of various different banners displayed in the app. However, we discovered that the Trojan Triada snook into one of these modified versions of the messenger called FMWhatsapp 16.80.0 together with the advertising software development kit (SDK). This is similar to what happened with APKPure, where the only malicious code that was embedded in the app was a payload downloader.