TL;DR: The main warning signs are the camera's indicator light turning on when you haven't opened any camera app, unfamiliar recordings or snapshots appearing on the device, or camera-related processes running in Task Manager or Activity Monitor that you didn't start. Check which apps have camera access under Settings > Privacy & Security > Camera (Mac/Windows have similar settings), run a reputable antivirus/anti-malware scan, revoke access from any app you don't recognize, and consider a physical camera cover as a low-effort backup.
The main warning signs are the camera's indicator light turning on when you haven't opened any camera app, unfamiliar recordings or snapshots appearing on the device, or camera-related processes running in Task Manager or Activity Monitor that you didn't start.
What Usually Causes This
Webcam access is usually hijacked through malware that gained permission during a prior app install, or through remote-access software installed without your knowledge.
What to Do About It
Check which apps have camera access under Settings > Privacy & Security > Camera (Mac/Windows have similar settings), run a reputable antivirus/anti-malware scan, revoke access from any app you don't recognize, and consider a physical camera cover as a low-effort backup.
If this looks similar to something else you've seen, it's worth reading How to Check If Your Old Devices Still Have Your Data.
This pattern shows up elsewhere too — see How to Check If Your Old Email Address Is Still a Weak Point.
Frequently Asked Questions
What are the real warning signs?
The main warning signs are the camera's indicator light turning on when you haven't opened any camera app, unfamiliar recordings or snapshots appearing on the device, or camera-related processes running in Task Manager or Activity Monitor that you didn't start.
What usually causes this?
Webcam access is usually hijacked through malware that gained permission during a prior app install, or through remote-access software installed without your knowledge.
What should I do about it?
Check which apps have camera access under Settings > Privacy & Security > Camera (Mac/Windows have similar settings), run a reputable antivirus/anti-malware scan, revoke access from any app you don't recognize, and consider a physical camera cover as a low-effort backup.
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.