ELI5: Explain Like I'm 5

Advanced Persistent Threat

An Advanced Persistent Threat (APT) is a type of cyber-attack that tries to break into a computer system or network and stay in it for a long time without being noticed. It usually tries to gain access to a system and then hide the attack by using strong encryption, so it can stay in the system and keep attacking it. The attacker usually targets a specific organization or individual, and tries to steal sensitive information from that organization or person. The attack can be very damaging, as the attacker can steal important documents, launch malicious software, or even damage the system completely. In short, an APT is a major security threat that can cause a lot of harm and should be prevented from happening.