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Insider Threat
Definition
An insider threat is a security risk originating from within the organization — employees, former employees, contractors, or business partners with access to systems who misuse that access.
An insider threat is a security risk originating from individuals within the organisation, including employees, former employees, contractors and business partners who misuse their authorised access to systems and data. According to the Ponemon Institute 2023 Cost of Insider Threats report, the average cost of insider incidents is $15.4 million per year per organisation.
How do insider threats work?
Insider threats are particularly dangerous because the threat actor already has legitimate access to systems, data and physical locations. They know internal processes, where valuable data resides and can bypass security measures designed for external threats.
Types of insider threats
Malicious insiders act intentionally: stealing data for personal gain, selling trade secrets to competitors, sabotaging systems out of revenge or spying for external actors. Negligent insiders cause unintentional damage through carelessness: clicking phishing links, accidentally sharing confidential files, ignoring security policies or losing devices. Compromised insiders are employees whose accounts have been taken over by external attackers via credential theft, malware or social engineering.
Impact on organisations
Insider threats account for a significant portion of all data breaches. Detection is complex because behaviour often resembles normal work activities. NIS2 requires appropriate measures against insider threats.
Protection
Implement User and Entity Behavior Analytics (UEBA) for anomalous user behaviour. Strictly apply least privilege. Monitor data transfers via DLP. Implement PAM for admin accounts. Conduct regular access reviews. Ensure adequate off-boarding procedures.
How DEFION helps
DEFION evaluates insider threat protection as part of Security Assessments. Red Teaming simulates insider scenarios. The MDR service monitors for insider activity indicators.