While most of the software is inserted by gaining access to computer networks, the NSA increasingly has made use of secret technology that enables it to enter and alter data in computers even if they are not connected to the Internet, according to NSA documents, computer experts and U.S. officials. The technology, which the agency has used 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.
The radio frequency technology has helped solve one of the biggest problems facing U.S. intelligence agencies for years: getting into computers that adversaries, and some U.S. partners, have tried to make impervious to spying or cyberattacks.
The NSA calls its efforts more an act of "active defense" against foreign cyberattacks than a tool to go on the offensive. But when Chinese attackers place similar software on the computer systems of U.S. companies or government agencies, U.S. officials have protested, often at the presidential level.
Among the most frequent targets of the NSA and its
"What's new here is the scale and the sophistication of the intelligence agency's ability to get into computers and networks to which no one has ever had access before," said
There is no evidence the NSA has implanted its software or used its radio frequency technology inside
"NSA's activities are focused and specifically deployed against - and only against - valid foreign intelligence targets in response to intelligence requirements,"