Tailored Access Operations
The Office of Tailored Access Operations (TAO), also known as Equation Group by Kaspersky or APT-C-40 by China, structured as S32, is a cyberwarfare intelligence-gathering unit of the National Security Agency (NSA). TAO identifies, monitors, infiltrates, and gathers intelligence on computer systems being used domestically and by entities foreign to the United States.
Source: Wikipedia — Tailored Access Operations (CC BY-SA 4.0)