Intrusion Posted on December 26, 2019May 8, 2020 by Ty Mezquita Image Source An intrusion is an unauthorized act of bypassing the security mechanisms of a network or information system. Synonyms: Intrusion Detection, Intrusion Prevention, Penetration Testing, Vulnerability Source: CNSSI 4009 Share this on your social networks. Help Friends, Family, and Colleagues become more aware and secure.