Tailored Access Operations

The Office of Tailored Access Operations (TAO), structured as S32, is a cyber-warfare intelligence-gathering unit of the National Security Agency (NSA). It has been active since at least 1998, possibly 1997, but was not named or structured as TAO until "the last days of 2000," according to General Michael Hayden.

TAO identifies, monitors, infiltrates, and gathers intelligence on computer systems being used by entities foreign to the United States. Provided by Wikipedia