Intrusion can occur physically, when the intruder enters the data center to access the data stored there, or when he or she attempts to access passwords, access authorizations, logins and authentications via a network or the Internet, bypassing authorization or other security measures.
Physical access can be achieved with tailgating; for access over networks, there are various attack techniques such as phishing, pretexting, baiting, and quid pro quo. Any intrusion, even an attempted one, is relevant under data protection law and criminal law. There are various defensive measures to ward off the intrusion. Intrusion Detection System( IDS) to detect the attempt, Intrusion Prevention System( IDP) to prevent it, NGFW firewalls and encryption techniques are just a few of many defense techniques.