We’ve been warning those attending our classes that its safer to stick with the official app stores like Google Play for Android. Google scans two million apps a week for potentially harmful apps. You don’t know what you’re getting if you download from a third party site. They’re unlikely to have as rigorous scanning process if they do any security scans at all.
Cybercriminals can take an existing app wrap it in malware and make it available on a third party site or link to an infected file in a phishing email. Beware of free versions of paid apps as they’ll likely include a nasty surprise.
You can avoid Android Malware. Google’s own statistics show that by downloading from the authorized play store is ten times safer than getting apps from other sources.