An advanced persistent threat (APT) is a sophisticated, sustained cyberattack by which an intruder establishes an undetected presence in the network in an effort to steal delicate facts about a protracted stretch of time. Network administrators who aspire to progress even further in their occupation choose blue group cybersecurity certifications https://www.researchgate.net/publication/365308473_Development_of_Cyber_Attack_Model_for_Private_Network