If your iPhone battery is draining fast or getting too warm, it may be being tapped. So, check the power consumption of your apps from Settings > Battery.
1. Notice battery behavior
Keep track of your daily/monthly data usage and check if there is a change in data consumption. Malicious software usually sends information to its server using your Wi-Fi/Mobile data.
2. Increased Mobile Data Usage
If you are seeing unusual amounts of ads in unusual places or have noticed apps installed on your iPhone without your knowledge, your iPhone could be tapped.
3. Unwanted Ads and Apps
If you have noticed an unusual performance drop, it might be because of the tapping in the background. Do note that an iPhone lags as it gets older.
4. Performance fall or lag
Suspicious SMS can be anything, including a randomized series of digits, characters, and symbols, which will immediately strike you as something odd. It's a sign that the device is being tapped.
5. Receiving suspicious messages
Are you hearing pulsating static or high-pitched humming on your iPhone? That might be because it's being tapped.
6. Unusual Background Noise
Unable to shut down your iPhone no matter how you try? It might be because the tapping software prevents you from canceling its operation.
7. Unable to shut down