Insider Threat
A security risk posed by current or former employees, contractors, or partners who misuse their legitimate access to cause financial harm or data theft.
Also known as: insider fraud, rogue employee fraud, internal threat
Last reviewed: 1 June 2026
Insider threats arise when someone with authorised access to systems, data, or physical assets abuses that access — whether for personal financial gain, at the direction of external criminals, or due to negligence. In a fraud context, insiders may steal customer data to sell on dark-web markets, manipulate financial records to divert funds, process fraudulent transactions, or act as recruited agents for organised criminal groups.
Insiders are particularly damaging because they bypass perimeter defences: they already have credentials, know where sensitive data lives, and may understand monitoring blind spots. Financial services, healthcare, and retail are common sectors for insider fraud due to the volume of payment and personal data handled.
Detection relies on user-and-entity-behaviour analytics (UEBA) that flag anomalous access patterns — downloading large volumes of data, accessing records outside normal role scope, or transacting at unusual times. Strong separation of duties, least-privilege access, and regular access reviews reduce both the opportunity and impact of insider fraud.
Examples
- A bank employee exports customer account details and sells them to a fraud ring that uses the data for vishing attacks.
- A payroll administrator creates ghost employees and routes their salaries to accounts they control.