Attention IT services in Australia: here’s something we need to be careful about for our clients’ (and our business’) safety. Do you know that there’s malware out there that can turn your PC into an eavesdropping device? Just as the speakers in your headphones turn electromagnetic signals into sound waves through a membrane’s vibrations, those membranes can also work in reverse, picking up sound vibrations and converting them back to electromagnetic signals – pretty scary stuff.
Recently, researchers at Ben-Gurion University of the Negev (BGU) have demonstrated malware that can turn computers into scary eavesdropping devices, even without the use of a microphone. That’s right – even without a microphone.
In their article titled “SPEAKE(a)R: Turn Speakers to Microphones for Fun and Profit,” the researchers explained and demonstrated how most PCs and laptops today are susceptible to this type of attack. Using SPEAKE(a)R – a malware that can covertly transform headphones into a pair of microphones – they show how easy it is for your gadgets to be compromised and used in devious ways.
“The fact that headphones, earphones and speakers are physically built like microphones and that an audio port’s role in the PC can be reprogrammed from output to input creates a vulnerability that can be abused by hackers,” states Prof. Yuval Elovici, director of the BGU Cyber Security Research Center (CSRC) and member of BGU’s Department of Information Systems Engineering.
“This is the reason people like Facebook Chairman and Chief Executive Officer Mark Zuckerberg tape up their mic and webcam,” relates Mordechai Guri, lead researcher and head of Research and Development at the CSRC. “You might tape the mic, but would be unlikely to tape the headphones or speakers,” he added.
Let’s look at the anatomy of a PC to further get an idea how this works. A typical computer setup contains audio jacks, either in the front panel, rear panel or both sides. Each jack is used either for input (line-in), or for output (line-out). The audio chipsets in modern motherboards and sound cards have an option for changing the function of an audio port with software – a type of audio port programming referred to as jack re-tasking or jack remapping.
Once your PC gets infected, malware can stealthily alter the functions of the headphone jack from a line-out jack to a microphone jack, making your headphones function as a pair of recording microphones and thus turning your computer into an eavesdropping device. This works even when the computer doesn’t have a connected microphone, according to the researchers.
The BGU researchers studied several attack scenarios to discover the signal quality of simple off-the-shelf headphones. “We demonstrated it is possible to acquire intelligible audio through earphones up to several meters away,” reveals Dr. Yosef Solewicz, an acoustic researcher at the BGU CSRC.
To protect your PC, you can set up safety measures, which include completely disabling audio hardware, using an HD audio driver to alert users when microphones are being accessed, and developing and enforcing a strict re-jacking policy, all of which may be implemented by IT support in Australia. Anti-malware and intrusion detection systems may also be used to monitor and detect unauthorized speaker-to-mic re-tasking operations by blocking them.
However, as we mentioned in our previous blog posts – the single biggest factor in preventing a malware infection on your PC IS YOU. You don’t need expert knowledge or special training to know that what you need is to be thorough and vigilant to avoid downloading and installing anything you do not understand or trust, no matter how tempting, from suspicious websites and emails.