performing-insider-threat-investigation

name	performing-insider-threat-investigation
description	Investigates insider threat incidents involving employees, contractors, or trusted partners who misuse authorized access to steal data, sabotage systems, or violate security policies, combining digital forensics, user behavior analytics, and HR/legal coordination to build an evidence-based case. Use when DLP alerts flag large data transfers to personal cloud storage or USB devices, when UBA detects anomalous access patterns for a user account, or when investigating employee data theft, privilege misuse, or internal threat detection requests.
domain	cybersecurity
subdomain	incident-response
tags	["insider-threat","user-behavior-analytics","data-exfiltration","privilege-misuse","DFIR"]
mitre_attack	["T1486","T1490","T1070","T1078","T1048"]
version	1.0.0
author	mahipal
license	Apache-2.0
nist_csf	["RS.MA-01","RS.MA-02","RS.AN-03","RC.RP-01"]

Performing Insider Threat Investigation

When to Use

• DLP (Data Loss Prevention) alerts on large data transfers to personal cloud storage or USB devices
• User behavior analytics (UBA) detects anomalous access patterns for a user account
• HR reports a departing employee suspected of taking proprietary information
• A privileged user is observed accessing systems outside their job function
• Whistleblower or coworker report alleges policy violations or data theft

Do not use for external attacker investigations where compromised credentials are used without insider collusion; use standard incident response procedures instead.

Prerequisites

• Legal counsel approval before initiating any monitoring or investigation of an employee
• HR partnership with defined investigation procedures and employee privacy guidelines
• DLP platform with content inspection and policy enforcement (Symantec DLP, Microsoft Purview, Digital Guardian)
• User behavior analytics platform (Microsoft Sentinel UEBA, Exabeam, Securonix)
• Forensic imaging capability for endpoint examination
• Chain of custody procedures for evidence that may be used in legal proceedings
• Clear authority and scope documentation approved by legal and HR

Workflow

Step 1: Receive and Validate the Allegation

Document the initial report and validate before proceeding:

• Record the source of the allegation (DLP alert, UBA detection, HR referral, manager report)
• Confirm with legal counsel that the investigation is authorized
• Define the investigation scope: what activity is being investigated, time period, systems involved
• Establish the investigation team: security, legal, HR (never investigate alone)
• Create a restricted case file accessible only to the investigation team

Investigation Authorization:
━━━━━━━━━━━━━━━━━━━━━━━━━━━
Case ID:           INV-2025-042
Subject:           [Employee Name] - [Title] - [Department]
Allegation:        Unauthorized transfer of proprietary data to personal cloud storage
Reported By:       DLP system alert + manager concern
Legal Approval:    [Counsel Name] - 2025-11-15
HR Liaison:        [HR Name]
Scope:             File access and transfer activity from 2025-10-01 to present
Systems in Scope:  Workstation, email, cloud storage, VPN, DLP logs

Step 2: Collect Evidence Covertly

Gather evidence without alerting the subject to the investigation:

Log-Based Evidence (non-intrusive):

• DLP logs: file transfers, policy violations, content matches