Why you should cover your webcam

On some laptop models, hackers can see you through your own webcam.

A man in California pleaded guilty last year to charges that he hacked into the computers of young women and used their webcams to take nude photos for an extortion scheme. Jared Abrahams, who will be sentenced in March, used malicious software to turn on the built-in cameras remotely.

Most laptops protect against such intrusions with small lights that go on whenever the camera is in use. However, new research from Johns Hopkins University in Baltimore shows that clever hackers can disable the indicator light on some computers, leaving people unaware that their webcam may be recording.

This raises new questions about how best to protect your privacy not only from what you do online but also what you do at home.

Crooks are not the only ones able to snoop on people using their own webcams.

The Federal Bureau of Investigation has acknowledged that it can digitally burrow into the computers of suspected criminals and use a machine's built-in camera to aid investigations. Getting permission to use this tactic, however, is a different question.

Last April, a magistrate judge in Houston denied the bureau's request to target an alleged online fraudster in the hopes of identifying the suspect. The judge ruled that the FBI needed more solid evidence before it could go fishing with a webcam.

A school district in Pennsylvania settled two lawsuits over allegations that administrators used tracking software on school-issued laptops to photograph students at home. And Canadian researchers suspect the Chinese government was behind snooping software set up to spy on the Dalai Lama.

This vulnerability comes from how manufacturers design their computers. Some camera lights are "hardware locked," meaning the webcam and the light are physically connected. One cannot be turned on without turning on the other. However, some models are "software locked" – a piece of code triggers the light. Hackers worm their way in by altering that code to hide their actions.

While the usual privacy tips apply here – update your security software! – the best defense may be the simplest: Whenever you're not using your webcam, cover the lens. A simple sticky note will do. Several groups sell custom-made covers, such as Camjamr, which offers sheets of stickers featuring cute animals or novelty mustaches, or C-Slide, which has designed a sliding shutter that blocks the lens.

For more on how technology intersects daily life, follow Chris on Twitter @venturenaut.