THE MOST SENSITIVE work environments, like nuclear power plants, demand the strictest security. Usually this is achieved by air-gapping computers from the Internet and preventing workers from inserting USB sticks into computers. When the work is classified or involves sensitive trade secrets, companies often also institute strict rules against bringing smartphones into the workspace, as these could easily be turned into unwitting listening devices.
But researchers in Israel have devised a new method for stealing data that bypasses all of these protections—using the GSM network, electromagnetic waves and a basic low-end mobile phone. The researchers are calling the finding a “breakthrough” in extracting data from air-gapped systems and say it serves as a warning to defense companies and others that they need to immediately “change their security guidelines and prohibit employees and visitors from bringing devices capable of intercepting RF signals,” says Yuval Elovici, director of the Cyber Security Research Center at Ben-Gurion University of the Negev, where the research was done.
“Attack requires both the targeted computer and the mobile phone to have malware installed on them”
The attack requires both the targeted computer and the mobile phone to have malware installed on them, but once this is done the attack exploits the natural capabilities of each device to exfiltrate data. Computers, for example, naturally emit electromagnetic radiation during their normal operation, and cell phones by their nature are “agile receivers” of such signals. These two factors combined create an “invitation for attackers seeking to exfiltrate data over a covert channel,” the researchers write in a paper about their findings.
The research builds on a previous attack the academics devised last year using a smartphone to wirelessly extract data from air-gapped computers. But that attack involved radio signals generated by a computer’s video card that get picked up by the FM radio receiver in a smartphone.
The new attack uses a different method for transmitting the data and infiltrates environments where even smartphones are restricted. It works with simple feature phones that often are allowed into sensitive environments where smartphone are not, because they have only voice and text-messaging capabilities and presumably can’t be turned into listening devices by spies. Intel’s manufacturing employees, for example, can only use “basic corporate-owned cell phones with voice and text messaging features” that have no camera, video, or Wi-Fi capability, according to a company white paper citing best practices for its factories. But the new research shows that even these basic Intel phones could present a risk to the company.
Photo from Johan Larsson via Flickr