The National Security Agency has implanted software in nearly 100,000 computers around the world that allows the agency to monitor those machines and can also create a digital highway for launching cyberattacks.
The New York Times reported that technology, which has been used by the agency since at least 2008, relies on a covert channel of radio waves that can be transmitted from tiny circuit boards and USB cards inserted surreptitiously into the computers.
In some cases, they are sent to a briefcase-size relay station that intelligence agencies can set up miles away from the target.