<!-- Copyright (c) 2026 defconxt. All rights reserved. -->
<!-- Licensed under AGPL-3.0 — see LICENSE file for details. -->
---
name: performing-threat-hunting-hypothesis
description: >-
  Develop and execute structured threat hunting hypotheses using ATT&CK-based
  methodology. Covers hypothesis formulation, data source identification,
  analytic development, hunt execution, and findings documentation.
domain: cybersecurity
subdomain: blue-team
tags:
  - threat-hunting
  - hypothesis-driven
  - mitre-attack
  - siem
  - detection-engineering
version: "1.0"
author: defconxt
license: AGPL-3.0
metadata:
  mitre-attack: []
  mitre-attack: []
---

# Performing Threat Hunting Hypothesis

## Overview

Hypothesis-driven threat hunting is a proactive security practice that formulates
testable assumptions about adversary behavior, then systematically validates or
refutes them using available telemetry. Unlike reactive alerting, hunting uncovers
threats that bypass existing detections.

## Prerequisites

| Requirement | Install |
|---|---|
| SIEM with search (Splunk/Elastic/Sentinel) | Query access to log data |
| ATT&CK Navigator | `attack-navigator` or web version |
| Jupyter Notebook | `pip install jupyterlab` for hunt notebooks |
| Python 3.10+ | Data analysis and agent tooling |
| Threat intelligence feeds | CTI context for hypothesis generation |

## Key Concepts

### Hypothesis Structure

```
HYPOTHESIS: [Adversary behavior] is occurring in [environment scope]
            detectable via [data source] by observing [observable pattern].

DATA SOURCES: [Required telemetry]
ANALYTICS:    [Specific queries or statistical methods]
TIMEFRAME:    [Hunt window]
PRIORITY:     [Based on threat model and likelihood]
```

### Example Hypotheses by ATT&CK Tactic

| Tactic | Hypothesis | Data Source |
|---|---|---|
| Initial Access | Phishing attachments spawning child processes from Office apps | Sysmon EID 1 (parent=WINWORD.EXE) |
| Execution | PowerShell downloading and executing remote scripts | Script Block Logging (EID 4104) |
| Persistence | Scheduled tasks created outside change windows | EID 4698 + change management correlation |
| Lateral Movement | PsExec-style remote service creation on multiple hosts | EID 7045 across endpoints |
| Exfiltration | Large DNS TXT queries to uncommon domains | DNS query logs, byte volume analysis |

### Hunt Execution SPL Queries

```spl
| -- Hypothesis: Attackers using LOLBins for download
index=sysmon EventCode=1
  (Image="*\\certutil.exe" CommandLine="*urlcache*")
  OR (Image="*\\bitsadmin.exe" CommandLine="*transfer*")
  OR (Image="*\\mshta.exe" CommandLine="*http*")
| stats count by Image, CommandLine, User, ComputerName
| sort -count

| -- Hypothesis: Lateral movement via remote service creation
index=wineventlog EventCode=7045
| stats count dc(ComputerName) AS target_count by ServiceName, ImagePath, AccountName
| where target_count > 3
| sort -target_count

| -- Hypothesis: Data staging before exfiltration
index=sysmon EventCode=11
  TargetFilename="*\\Temp\\*.zip" OR TargetFilename="*\\Temp\\*.rar"
  OR TargetFilename="*\\Temp\\*.7z"
| stats count by Image, TargetFilename, User
| where count > 5
```

### Hunt Documentation Template

```markdown
# Hunt Report: [Hunt Name]
## Hypothesis
[Statement of what was being tested]
## Data Sources
[What telemetry was analyzed]
## Methodology
[Queries, tools, statistical methods used]
## Findings
[What was discovered — true/false/inconclusive]
## Indicators
[IOCs, suspicious patterns discovered]
## Detection Gap
[What existing detection missed and recommended new rules]
## Recommendations
[Specific actions: new detections, policy changes, hardening]
```

## Workflow

1. **Generate hypothesis** — Use threat intel, ATT&CK, or red team reports
2. **Identify data sources** — Map hypothesis to required telemetry
3. **Validate data availability** — Confirm logs exist and are indexed
4. **Develop analytics** — Write queries or statistical models
5. **Execute hunt** — Run analytics across defined timeframe
6. **Analyze results** — Triage findings, separate true/false positives
7. **Document** — Write hunt report with findings and recommendations
8. **Produce detections** — Convert validated findings into automated rules

## Verification

| Check | Method |
|---|---|
| Hypothesis is testable | Maps to specific data source and observable |
| Data sources available | Index contains events for hunt timeframe |
| Analytics return results | Queries execute without error |
| Findings documented | Hunt report follows template |
| Detections produced | New Sigma rules created from confirmed findings |

## References

- [MITRE ATT&CK](https://attack.mitre.org/)
- [TaHiTI Threat Hunting Methodology](https://www.betaalvereniging.nl/en/safety/tahiti/)
- [PEAK Threat Hunting Framework](https://www.splunk.com/en_us/blog/security/peak-threat-hunting-framework.html)
- [Sqrrl Threat Hunting Reference](https://www.threathunting.net/sqrrl-archive)
