The New York Times wrote N.S.A. Devises Radio Pathway Into Computers. It describes how the NSA has implanted hardware in targeted machines that communicates via radio waves. This means the machines don't need to be connected to the Internet to send info to the NSA, they just need to broadcast to a radio receiver that could be miles away.
"One, called Cottonmouth I, looks like a normal USB plug but has a tiny transceiver buried in it. According to the catalog, it transmits information swept from the computer ‘through a covert channel’ that allows ‘data infiltration and exfiltration.’ Another variant of the technology involves tiny circuit boards that can be inserted in a laptop computer — either in the field or when they are shipped from manufacturers — so that the computer is broadcasting to the N.S.A. even while the computer’s user enjoys the false confidence that being walled off from the Internet constitutes real protection.
The relay station it communicates with, called Nightstand, fits in an oversize briefcase, and the system can attack a computer ‘from as far away as eight miles under ideal environmental conditions.’ It can also insert packets of data in milliseconds, meaning that a false message or piece of programming can outrace a real one to a target computer. Similar stations create a link between the target computers and the N.S.A., even if the machines are isolated from the Internet.
Computers are not the only targets. Dropoutjeep attacks iPhones. Other hardware and software are designed to infect large network servers, including those made by the Chinese."