According to the cybersecurity specialists Zimperium, a non-Google Play Store app masquerading as a system-update tool found online is in fact Android malware. Once installed on devices via side-loading, it apparently steals information ranging from SMS messages to clipboard data. It may also hijack phone cameras and mics to spy on unsuspecting users.
https://www.notebookcheck.net/An-Android-app-calling-itself-System-Update-is-unmasked-as-malware-by-a-security-company.529946.0.html