Most webcams have a warning light that indicates when they're active, but it's possible for malware to disable this important privacy feature on older Mac computers, according to research from Johns Hopkins University (JHU) in Baltimore. JHU Assistant Research Professor Stephen Checkoway and graduate student Matthew Brocker investigated the hardware design of the first-generation iSight webcam model installed in Apple's iMac and MacBook computers released before 2008 and found that its firmware could easily be modified to disable the indicator LED.