Per The Hacker News, researchers have developed a novel method called TrojPix that can extract data from air-gapped computers by subtly manipulating on-screen pixels to emit radio signals.
The TrojPix technique, developed by Shandong University researchers, exploits the video cable to radiate faint radio signals that can be captured by a nearby receiver. This method requires malware to be present on the target machine, acting as an exfiltration channel rather than an entry point. In tests, TrojPix achieved a peak throughput of 8.1 Mbps, significantly faster than previous air-gap covert channels, enabling the transfer of large files in minutes. The technique does not require administrator rights or hardware modifications, with user-level malware capable of drawing to the screen being sufficient. It can operate by faking a powered-off display or by embedding signals within ordinary on-screen content. The method has been demonstrated across multiple monitor brands and video cables.
While previous research has explored similar electromagnetic emanations, TrojPix offers a substantially higher data transfer rate. Unlike air-gap attacks seen in the wild, which often use USB drives, TrojPix leverages radio signals. Countermeasures include using fiber-optic video links, shielding sensitive areas, and, most importantly, preventing malware infection in the first place.
Source: The Hacker News
