TAO is not your average band of hackers. Its operations have included digging into China’s networks, developing the tools British spies used to break into Belgium’s largest telecom, and hacking sections of the Mexican government. While other parts of the NSA may focus on tapping undersea cables or prying data from Silicon Valley giants, TAO is the tip of the NSA’s offensive hacking spear, and could have access to much more sensitive information ripped from adversaries’ closed networks. The unit deploys and creates sophisticated exploits that rely on vulnerabilities in routers, operating systems, and computer hardware the general population uses—the sort of tools that could wreak havoc if they fell into the wrong hands.

That doesn’t mean those tools are locked down, though. “TAO specifically had a huge amount of latitude to move data between networks,” the first source, who worked at the unit after Edward Snowden’s mega-leak, said. The former employee said TAO limited the number of USB drives—which could be used to steal data—after that 2013 breach, but he still had used several while working at TAO.