Sudden battery drain
Phone overheating when idle
Unusual data usage spikes
Random pop-ups or ads
Apps you did not install
Settings changed without your action
Unknown calls or texts sent from your phone
Contacts receiving strange messages from you
Frequent crashes or freezing
Slow performance
Microphone or camera turning on unexpectedly
Strange background noise during calls
Login alerts from accounts you did not access
Passwords changing without your input
Unknown devices signed into your accounts
Browser redirects to unfamiliar sites
Security apps disabled or missing
Phone restarts on its own
Unfamiliar files, folders, or permissions
SIM card issues or no service unexpectedly