While installing APKs from outside the Play Store is not illegal, it can void warranties or violate the Terms of Service for certain apps.
When you download an application from the Google Play Store , the Android system extracts a file usually named base.apk into the device's internal storage. Download basemo3ad apk
Before installing, you can upload the file to VirusTotal to scan it against dozens of antivirus engines. While installing APKs from outside the Play Store