TL;DR: Watch for unexpected battery drain, the device running hot even when idle, unfamiliar apps or configuration profiles you didn't install, and a spike in cellular data usage you can't account for. Go to Settings > General > VPN & Device Management to check for unrecognized profiles, review Settings > Privacy & Security > App Privacy Report for unusual app activity, update iOS immediately, and if symptoms persist use Settings > General > Transfer or Reset iPhone > Erase All Content and Settings as a last resort.
Watch for unexpected battery drain, the device running hot even when idle, unfamiliar apps or configuration profiles you didn't install, and a spike in cellular data usage you can't account for.
What Usually Causes This
These symptoms usually trace back to a malicious app installed outside the App Store, a rogue configuration profile granting elevated access, or in rare targeted cases a zero-click spyware exploit.
What to Do About It
Go to Settings > General > VPN & Device Management to check for unrecognized profiles, review Settings > Privacy & Security > App Privacy Report for unusual app activity, update iOS immediately, and if symptoms persist use Settings > General > Transfer or Reset iPhone > Erase All Content and Settings as a last resort.
If this looks similar to something else you've seen, it's worth reading Is My Laptop Hacked? Signs to Look For.
This pattern shows up elsewhere too — see How to Check If Your Printer Is a Security Risk.
Frequently Asked Questions
What are the real warning signs?
Watch for unexpected battery drain, the device running hot even when idle, unfamiliar apps or configuration profiles you didn't install, and a spike in cellular data usage you can't account for.
What usually causes this?
These symptoms usually trace back to a malicious app installed outside the App Store, a rogue configuration profile granting elevated access, or in rare targeted cases a zero-click spyware exploit.
What should I do about it?
Go to Settings > General > VPN & Device Management to check for unrecognized profiles, review Settings > Privacy & Security > App Privacy Report for unusual app activity, update iOS immediately, and if symptoms persist use Settings > General > Transfer or Reset iPhone > Erase All Content and Settings as a last resort.
Should I be worried if I only see one sign?
One sign alone (like a slower device) is usually not cause for alarm — most single symptoms have mundane explanations. Multiple signs together, especially unexpected data usage or unfamiliar apps, are worth investigating.