Think because that light is dark, your webcam isn’t on? Think again.
Webcam spying may have just gotten a little bit easier. According to new research from Johns Hopkins University, it is possible on some older Mac computers for malware to disable the warning light that indicates the webcam is on. In a new paper, Johns Hopkins graduate student Matt Brocker and Assistant Research Professor Stephen Checkoway revealed that there is a way to disable the LED [light-emitting diode] on certain Apple internal iSight webcams used in versions of MacBook laptops and iMac desktops.
“The same technique that allows us to disable the LED, namely reprogramming the firmware that runs on the iSight, enables a virtual machine escape whereby malware running inside a virtual machine reprograms the camera to act as a USB Human Interface Device (HID) keyboard which executes code in the host operating system,” the researchers wrote. “We [built] two proofs-of-concept: (1) an OS X application, iSeeYou, which demonstrates capturing video with the LED disabled; and (2) a virtual machine escape that launches Terminal.app and runs shell commands.”
The researchers looked at webcams installed in iMac and MacBook computers released prior to 2008 for their study.
“Disabling the indicator LED on the iSight entails two requirements,” they wrote. “First…the indicator LED is directly connected to the STANDBY pin on the image sensor. In order to disable the LED, we need to keep STANDBY asserted. Since asserting STANDBY will disable the image sensor output, we need to configure the image sensor to ignore STANDBY before we assert this signal. Second, we need a way to modify the firmware on the EZ-USB to in order to configure the image sensor appropriately as well as keep STANDBY asserted whenever we want the LED to stay off.”
The researchers also presented possible hardware and software changes that can prevent their attack. In the future, the researchers said they plan to examine newer webcams as well.
“There has been a long and sordid history of internet perverts and peeping Toms hacking into computers, and secretly taking images and videos of their victims via the webcam,” blogged security researcher Graham Cluley. “One recent victim was Miss Teen USA Cassidy Wolf, who was secretly spied upon in her bedroom by a hacker who took photographs and threatened to release them to the public.”
“Whether the hackers are doing it for sexual kicks or with the intention of blackmail doesn’t really matter – it’s a gross invasion of privacy, and can leave the victim feeling shaken and abused,” he added.
