performing-insider-threat-investigation

Collect non-intrusive log evidence first: DLP alerts, cloud storage activity, email gateway records, VPN logs, and badge access data. Obtain legal counsel approval before any monitoring, restrict case file access to the investigation team, and image the endpoint before the subject's last day.

Microsoft Purview provides insider risk management and DLP, Exabeam and Securonix deliver UEBA anomaly detection, and Digital Guardian monitors endpoint exfiltration. Magnet AXIOM supports forensic analysis of endpoint, cloud, and mobile evidence.

Insiders often drip 20-50MB per day to personal webmail or sanctioned cloud tenants, staying under DLP thresholds. Detect this by baselining each user's 3-6 month normal volume, destinations, and hours, then alerting on sustained deviation rather than single large transfers.

Do not use them for external attackers using compromised credentials without insider collusion; standard incident response applies instead. Also avoid investigating without legal authorization, as unauthorized employee monitoring may violate privacy rights and destroy case admissibility.

Maintain strict chain of custody, hash all evidence files with an integrity log, and document every analysis step so another examiner can reproduce results. Store evidence in an access-controlled repository with audit logging and retain it per legal hold requirements.