A sophisticated persistent threat (APT) is a complicated, sustained cyberattack by which an intruder establishes an undetected existence in a network so as to steal delicate data more than a protracted timeframe. Intrusion detection methods make a database of recognised attack techniques to establish designs and thwart any identical incidents https://www.researchgate.net/publication/365308473_Development_of_Cyber_Attack_Model_for_Private_Network