The term Advanced Persistent Threats (APT) was first coined by the U.S. Government during 2005 by Security Analysts to describe complex cyber attacks against specific targets for financial or informational gains by a well-funded group of individuals. APTs (aka Advanced Persistent Attacks) are designed to gain access to a network, acquire data and secretly monitor the targeted computer systems over long periods of time. The Stuxnet computer worm, which targeted the computer hardware of Iran’s nuclear program, is one example.”]
Source: https://securityaffairs.co/wordpress/33999/cyber-crime/apt-and-avt-techniques.html