threat-hunting

threat-hunting is a cursor rule for Cursor from briiirussell/cybersecurity-skills. It costs 123 tokens per session (2,906 once invoked), scanned C, original, MIT.

A security investigation method for looking through SIEM, endpoint, and other logs for attackers who have not triggered an alert. It uses specific, testable questions based on MITRE ATT&CK, a catalogue of attacker techniques.

In plain words
What is it for?
Use it to plan and run proactive hunts for attacker techniques, review evidence from security tools, and turn useful hunt queries into future detection rules.
Why use it?
It helps find suspicious activity that automatic alerts missed. It also gives the search a clear purpose instead of encouraging unfocused browsing through logs.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

Good fit Use it to plan and run proactive hunts for attacker techniques, review evidence from security tools, and turn useful hunt queries into future detection rules.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/briiirussell/cybersecurity-skills/threat-hunting
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo
git clone --depth 1 https://github.com/briiirussell/cybersecurity-skills

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for threat-hunting

README.md
[![agentmods](https://agentmods.dev/badge/rules/briiirussell/cybersecurity-skills/threat-hunting/github.svg)](https://agentmods.dev/rules/briiirussell/cybersecurity-skills/threat-hunting)
Your own site
<a href="https://agentmods.dev/rules/briiirussell/cybersecurity-skills/threat-hunting"><img src="https://agentmods.dev/badge/rules/briiirussell/cybersecurity-skills/threat-hunting/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for threat-hunting

Your own site · 80×15
<a href="https://agentmods.dev/rules/briiirussell/cybersecurity-skills/threat-hunting"><img src="https://agentmods.dev/badge/rules/briiirussell/cybersecurity-skills/threat-hunting.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 123 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,906 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00123 $0.02906
Opus 5.5 $0.00049 $0.01162
Sonnet 5.5 $0.00025 $0.00581
Haiku 4.5 $0.00012 $0.00291

Measured today against content hash 18a63d8b5da0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

threat-hunting scanned grade C with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Cloud metadata endpointhighServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

- **IMDS access from unusual processes / containers** — anything reaching `169.254.169.254` that isn't the cloud SDK
adapters/cursor/threat-hunting.mdc · 230 lines

How it starts

The opening of the file, as written. The whole thing — 230 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Threat Hunting — Proactive Adversary Detection

Hunt for adversaries who are already inside but haven't tripped an alert. Distinct from incident-triage (reactive, alert is firing) and from siem-detection (engineer rules so future alerts fire). This skill is the proactive layer — assume something has slipped through, look for it.

Hunting is hypothesis-driven, not browse-driven. "Let's look around the SIEM" is not hunting; "let's check for the specific pattern of T1059.001 (PowerShell) being launched by Office processes" is.

Cross-references: siem-detection (queries you write here often graduate to detection rules), incident-triage (what to do if a hunt confirms a finding), breach-patterns (a rich source of hunt hypotheses), disk-forensics (deeper analysis on confirmed hits), agent-supply-chain-audit (hunting for malicious or rug-pulled AI coding-agent extensions on developer machines), secrets-audit (its exfiltration-collector domain list is a ready-made egress hunt: DNS / proxy hits to webhook.site, requestbin, ngrok, or chat webhooks from servers or CI runners).

Authorization

Hunt only in environments the user owns or is authorized to investigate, with the logs and telemetry they've given you access to. Hunting reads; it doesn't contain. If a hunt finds confirmed malicious activity, stop and hand off to incident-triage instead of acting on hosts or accounts. Hunting in employee activity stays within what HR and legal have authorized.

Methodology — PEAK framework

The PEAK (Prepare, Execute, Act, Knowledge) framework from Splunk SURGe — the most actionable hunting methodology I've seen.

Step 1: Prepare

Form the hypothesis. Strong hypotheses share three properties:

  1. Specific — names a technique, log source, and expected artifact
  2. Testable — describes what evidence would confirm or deny
  3. Bounded — has a defined time window and scope

Bad hypothesis: "Look for anomalies in the SIEM" Good hypothesis: "Within the last 30 days, no service account should have run interactive PowerShell with -encodedCommand flag (T1059.001 + T1027). Search Sysmon event 1 for parent process = service-account-launched scheduled task, child = powershell.exe, command line contains -enc or -encodedcommand."

Read the full file on GitHub · 230 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. today Changed · +4 lines 18a63d8b5da0
  2. 1mo ago First seen · 226 lines · 123 tokens per session scan C 1f975dea9832

Subscribe to this mod's changes

threat-hunting is a cursor rule published in the GitHub repository briiirussell/cybersecurity-skills (435 stars, last pushed today), licensed MIT. It adds 123 tokens to every session and 2,906 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it C with 1 finding (cloud metadata endpoint). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.