An insider threat is a risk that comes from someone who already holds legitimate access: an employee, contractor, business partner, or a former staffer whose credentials were never revoked. What makes these threats hard to catch is that the access itself is authorized, so activity that would look alarming from an outsider reads as normal from a trusted account.
Insiders generally split into two types. Malicious insiders act on purpose, stealing data or sabotaging systems for money, revenge, or a competitor. Negligent insiders mean no harm but cause it anyway, through a misconfigured server, a fat-fingered permission, or a phishing link that hands their account to someone else. The negligent group is far more common, yet organizations tend to over-invest in catching the rare saboteur while everyday mistakes do most of the damage. Defense leans on user behavior analytics, least privilege, separation of duties, and monitoring that spots access out of step with a person’s normal role.
How are insider threats tested on the CISSP?
Insider threats cut across Domain 7: Security Operations, Identity and Access Management, and Security and Risk Management. Know behavior analytics, access controls, separation of duties, and the monitoring that surfaces insider activity. CISA publishes insider threat mitigation resources.
Related terms: Separation of Duties, Security Audit