Threat Hunting Skill for Claude

Use when hunting threats or engineering detections — ATT&CK Detection-Strategies, Sigma + correlation with Detection-as-Code CI, Windows endpoint hunting (Sysmon/ETW/LSASS/LOLBins), network C2 hunting (JA4+, beaconing, DNS tunneling), cloud-identity hunting, Atomic Red Team purple-team validation

30k tokens

context cost

the whole folder, loaded on every use

files

ships runnable scripts

copies elsewhere

how many repositories repackaged it

334

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/hypnguyen1209/offensive-claude --skill threat-hunting

What comes with it

109 144 bytes besides the instruction

references/cloud-identity-hunting.md

references/methodology-hunt-loop.md

references/network-c2-hunting.md

references/purple-team-validation.md

references/sigma-rule-engineering.md

references/windows-endpoint-hunting.md

scripts/beacon_hunter.py

scripts/cloudtrail_hunt.py

scripts/coverage_matrix.py

scripts/dac_validate.py

scripts/entra_hunt.kql

scripts/evtx_hunt.py

scripts/sigma_pipeline.sh

scripts/sysmon_config_2025.xml

The instruction itself

6 sections, as written by the author

Threat Hunting & Detection Engineering

When to Activate

Hypothesis-driven hunting across endpoint, network, cloud, and identity telemetry
Writing & shipping detections (Sigma + correlation) as version-controlled code in CI
Mapping & measuring coverage against MITRE ATT&CK v18 (Detection Strategies / Analytics)
Hunting Windows post-exploitation: ETW/AMSI tampering, LSASS dumping, LOLBins, injection
Hunting C2 in encrypted traffic: JA4+/JA4X fingerprints, beaconing, DNS tunneling
Hunting cloud-identity attacks: Entra device-code/OAuth phishing, PRT theft, CloudTrail abuse
Purple-team validation: emulate ATT&CK with Atomic Red Team/Caldera, find detection gaps
Triaging EVTX/Zeek/CloudTrail offline during IR without a SIEM

Technique Map

|-----------|--------|-----|-----------|--------|

| Hypothesis-driven hunt loop (PEAK/TaHiTI) | TA0043 | CWE-778 | references/methodology-hunt-loop.md | - |

Quick Start

# 0. Deploy hunting telemetry baseline (Sysmon 15+, PPL self-protected)
sysmon -accepteula -i scripts/sysmon_config_2025.xml      # or: sysmon -c <file> to update

# 1. Offline endpoint triage over collected EVTX (no SIEM)
python3 scripts/evtx_hunt.py /cases/host01/EVTX --min-severity medium --json host01.json

# 2. Network: hunt C2 beacons / DNS tunneling over Zeek logs (+ optional JA4 blocklist)
zeek -r capture.pcap LogAscii::use_json=T
python3 scripts/beacon_hunter.py --conn conn.log --dns dns.log \
        --ja4-blocklist bad_ja4.txt --min-score 0.7

# 3. Cloud/identity: paste scripts/entra_hunt.kql into Sentinel/Defender;
#    triage AWS offline:
python3 scripts/cloudtrail_hunt.py /cases/cloudtrail/ --json ct_findings.json

# 4. Detection-as-Code: lint + compile your Sigma repo for CI (fail-fast)
python3 scripts/dac_validate.py rules/ --backend splunk --pipeline sysmon --fail-on-error
./scripts/sigma_pipeline.sh rules/ build/ splunk microsoft365defender elasticsearch

# 5. Purple-team validate + measure coverage (ATT&CK v18 Navigator layer + gaps)
Invoke-AtomicTest T1003.001 -TestNumbers 1,2,3   # lab only; -Cleanup after
python3 scripts/coverage_matrix.py --rules rules/ --atomic-results atomic_results.json \
        --watchlist watchlist.txt --navigator-out attack_layer.json --gaps-out gaps.csv

OPSEC & Detection (summary)

|-----------|-----------------|--------------------------|------------|

| ETW/AMSI patch | RWX in ntdll/amsi; ScriptBlock w/ AmsiScanBuffer+VirtualProtect | Sigma AMSI/ETW patch rule; Sysmon EID 25; ETW-TI (kernel) | Userland patch defeats single source — correlate EID25 + ETW-TI + behavior |

| Sysmon kill | System 7036/7034, SysmonDrv unload, EPS drop to 0 | Visibility-gap metric on chatty hosts | Sysmon 15 is PPL; attacker kills agent instead — alert on stop/unload |

| LSASS dump | EID 10 handle to lsass + .dmp write | LSASS-access Sigma; access-mask + non-system source | Baseline your own EDR/AV SourceImage set first or you flood the SOC |

| Beaconing | periodic intervals, uniform sizes, low prevalence | beacon_hunter.py CV<0.3; RITA; long-conn on non-interactive port | Need days of logs — small PCAPs inflate FPs |

| JA4X C2 | randomized certs sharing one JA4X (Sliver/Havoc) | JA4 segment-pivot; JA4X blocklist at TLS-terminating proxy | TLS 1.3 encrypts certs — capture at egress/proxy, don't block on FP alone |

| DNS tunneling | long/high-entropy subdomains, TXT volume, NXDOMAIN spikes | DNS entropy/volume scoring; DoH-to-public Sigma | Baseline normal long-FQDN apps (CDNs) before alerting |

| Device-code phish | deviceCode sign-in, broker/OfficeHome AppId, new ASN | entra_hunt.kql #1+#2; Elastic open rules | Baseline sanctioned device-code apps; not every device-code is evil |

| PRT theft | primaryRefreshToken from multi-geo same day | PRT KQL + LSASS/cloudAP endpoint join | Control-plane is the ONLY evidence — retain logs ≥90d before you need them |

| CloudTrail abuse | StopLogging/DeleteTrail, CreateAccessKey for others, Describe* burst | cloudtrail_hunt.py; Athena tamper query | Attackers disable logging early; enable org-wide all-region trail up front |

Deep Dives

references/methodology-hunt-loop.md — PEAK/TaHiTI hunt loop, ATT&CK v18 Detection Strategies (DETxxxx) & Analytics (ANxxxx) replacing legacy data sources, Detection-as-Code CI/CD (PTEFv4), visibility-gap detection.
references/windows-endpoint-hunting.md — Sysmon 15 PPL & tamper detection, ETW/AMSI in-memory patch detection (ETW-TI, EID 25, ScriptBlock), LSASS handle hunting, LOLBins & process-tree anomalies.
references/sigma-rule-engineering.md — Sigma rule anatomy, correlation rules (value_count/temporal), pySigma/sigma-cli compile, Hayabusa/Chainsaw/Velociraptor 0.74 native-Sigma EVTX triage, AI-assisted authoring (SigmaGen/Uncoder).
references/network-c2-hunting.md — JA4+/JA4S/JA4H/JA4X fingerprinting, Sliver/Havoc shared JA4X, RITA-style beaconing & long-connection stats, DNS tunneling/DGA/DoH, C2 framework signature cheat-sheet.
references/cloud-identity-hunting.md — Entra device-code phishing (STORM-2372, Tycoon2FA, EvilTokens), OAuth consent abuse, PRT theft, Graph enumeration, AWS CloudTrail abuse & tampering.
references/purple-team-validation.md — Atomic Red Team unit tests, MITRE Caldera chained emulation, ATT&CK v18-aware coverage matrix, Navigator layer generation, prioritized gap analysis.

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How to use it

Copy the folder

Take hypnguyen1209/threat-hunting from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

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