The secret contract was finalized on Nov. 8, 2021, a deal between a company that has acted as a front for the United States government and the American affiliate of a notorious Israeli hacking firm. Under the arrangement, the Israeli firm, NSO Group, gave the U.S. government access to one of its most powerful weapons a geolocation tool that can covertly track mobile phones around the world without the phone user's knowledge or consent. Only five days earlier, the Biden administration had announced it was taking action against NSO, whose hacking tools for years had been abused by governments around the world to spy on political dissidents, human rights activists and journalists. The White House placed NSO on a Commerce Department blacklist, declaring the company a national security threat. The secret contract ... violates the Biden administration's public policy, and still appears to be active. The contract, reviewed by The Times, stated that the "United States government" would be the ultimate user of the tool, although it is unclear which government agency authorized the deal and might be using the spyware. Elements of America's expansive national security apparatus in recent years have bought the weapons, deployed them against drug traffickers, and have quietly pushed to consolidate control of them into the hands of the United States and its closest allies. The F.B.I. purchased access in 2019 to NSO's most powerful hacking tool, known as Pegasus, which invades mobile phones and mines their contents.