Performing Insider Threat Investigation

Performing Insider Threat Investigation

Overview

Cybersecurity skill for performing insider threat investigation. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "performing insider threat investigation"

• "Investigates insider threat incidents involving employees, contractors, or trust"

• 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.

When NOT to Use

• When you lack proper authorization for testing
• For production systems without change management
• When the task requires legal or compliance expertise beyond technical scope

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

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Plan Operations — Define objectives, scope, and success criteria for insider threat investigation operations.
2. Prepare Environment — Set up tools, access, and data sources required for insider threat investigation.
3. Execute Core Workflow — Perform the insider threat investigation operations following established procedures.
4. Validate Results — Verify that results meet quality standards and objectives.
5. Report Findings — Document results, observations, and recommendations.
6. Follow Up — Track remediation actions and verify fixes where applicable.

Tools

• Analysis Platform — Data processing and visualization
• Collaboration Tools — Team coordination and knowledge sharing

Process

1. Design — Define interface, identify patterns, plan implementation
2. Implement — Write code following existing conventions, add tests
3. Verify — Run tests, check integration, validate behavior

Verification

• All insider threat investigation procedures executed completely and documented
• Findings validated against multiple data sources
• False positives identified and filtered
• Results documented with evidence and timestamps
• Recommendations provided with risk-based prioritization

Anti-Rationalization Table