According to recent research by The Washington Post, there is a way with the help of which anyone can hijack a MacBook’s Camera without even triggering the warning light (a feature which is used to tell users when they’re being watched).
A Computer Scientist Stephen Checkoway has figured out this. According to the research details, iSight Camera’s micro-controller chip establishes a hardware-level interlock between the camera and the warning light. So, when the camera is enabled it automatically enables the warning light. But if you know how to remotely reprogram the chip as Stephen Checkoway does, then you can access the camera without enabling the light. But currently it works only on MacBooks which were released before 2008. The article also suggests that, there could be a similar security hole in modern cameras too.
Source: Washington Post