In most cases, it’s easy for Mac users to know whether or not their webcam is watching them. Both on Macbook Pros or  iMacs, laptops or desktops, Macs always come with a green LED indicator light that reveals whether or not the webcam is active. However, according to a report posted on DigitalTrends.com, two researchers from John Hopkins University recently authored a scholarly paper about how internet spies can actually disable that LED indicator and spy on Mac users without their knowledge.

The paper, called “iSeeYou: Disabling the MacBook Webcam Indicator LED” and authored by Matthew Brocker and Stephen Checkoway, explains how a piece of Mac OS X software called iSeeYou can be used to effectively hamper the webcam indicator light. Once the light is disabled, internet snoops can make it so the camera stays on at all times without the computer user knowing it.

The ability of iSeeYou to breach privacy has already made its way into the news headlines. Earlier this week, it was reported that Cassidy Wolf, the reigning “Miss Teen USA,” had had her Macbook Pro’s webcam compromised by a classmate. The young beauty pageant queen was spied on a male classmate, who used iSeeYou to turn off the LED on her Macbook webcam (also called the “iSight”), and while it appears that nothing scandalous came out of the incident, Wolf’s predicament shows just how easy it is for a snoop to turn a Mac computer into a surveillance device.

Rather than just further propagating the spying method, Brocker and Checkoway also developed a free piece of software called iSightDefender, which can be used to block the privacy invasions that iSeeYou allows. The software can be used with Mac OS X version 10.6, but is supposedly only really necessary for 2007 and 2008 Macs. Brocker and Checkoway believe that newer versions of Apple’s computers are more secure and cannot have their webcams broken into so easily, though conflicting reports have called that thought into question. More recent Mac models may well have their own webcam security vulnerabilities, and Apple users would be wise to install iSightDefender just to be safe, regardless of computer model.

Still, the ease with which iSeeYou allows snoops to abuse the functions of a webcam poses greater security questions for Apple computers and webcams in general. Rumors have also circulated that the government is using similarly invasive methods to spy on citizens, a factor which may cause future computer users to call for webcams that can be more easily covered up or shut off.