# Performing Insider Threat Investigation

> Use when investigates insider threat incidents involving employees, contractors, or trusted partners who misuse authorized access to steal data, sabotage systems, or violate security policies. Combines digital forensics, user behavior analytics, and HR/legal coordination to build an evidence-based case. Activates for requests involving insider threat investigation, employee data theft, privilege misuse, user behavior anomaly, or internal threat detection. '.

- Skill: `oyi77/performing-insider-threat-investigation` (Agent Skill)
- Install (CLI): `npx skillmds add oyi77/performing-insider-threat-investigation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/oyi77/performing-insider-threat-investigation/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- License: Apache-2.0
- Author: oyi77 (https://skillmd.com/u/oyi77)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/oyi77/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

```python
# 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
1. **Implement** — Write code following existing conventions, add tests
1. **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

| Rationalization | Reality |
|---|---|
| "We are too small to be targeted" | Automated attacks target everyone. Size does not matter. |
| "Security slows us down" | A breach slows you down 100x more. Build security in from the start. |
| "We will fix it after launch" | Vulnerabilities in production are exploited within hours. Fix before deploy. |