api-fuzzing-bug-bounty

api-fuzzing-bug-bounty is a skill for Claude Code from sickn33/agentic-awesome-skills. It costs 48 tokens per session (2,963 once invoked), scanned A, original, MIT.

A guide to testing REST, SOAP, and GraphQL APIs for security weaknesses, including input fuzzing, authentication bypasses, and insecure object access. It is intended only for systems where you have written permission to test.

In plain words
What is it for?
Use it during authorized penetration tests, bug-bounty work, or controlled lab exercises to assess API authentication, access control, and unexpected input handling.
Why use it?
It adds a safety checkpoint before any probing or exploitation and keeps testing within an agreed scope. It helps security testers look for API-specific flaws without treating an unauthorized target as acceptable.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the agentic-awesome-skills plugin — 196 skills shipped together

not rated 46krepo +260 3d ago A scan Socket: warnSnyk: failSkillSpector: warn 48 tokens original MIT

Good fit Use it during authorized penetration tests, bug-bounty work, or controlled lab exercises to assess API authentication, access control, and unexpected input handling.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty
About the project

AAS Core is a local control plane for coding agents that lets them search a large catalogue of skills, choose a stack, validate it, and create a reproducible plan. It is used to assemble and review agent workflows through its CLI, local MCP server, catalogue, plugins, and Workbench. The catalogue add-ons provide the skills, plugins, bundles, and workflows that AAS Core helps agents select and validate.

sickn33/agentic-awesome-skills · 46,288 stars · on GitHub · sickn33.github.io

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.

Any agent
npx skills add sickn33/agentic-awesome-skills --skill api-fuzzing-bug-bounty
Clone the repo
git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills

Made for: Claude Code.

Or install agentic-awesome-skills, the plugin that ships this one along with the rest of its 196 skills.

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 api-fuzzing-bug-bounty

README.md
[![agentmods](https://agentmods.dev/badge/skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty/github.svg)](https://agentmods.dev/skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty)
Your own site
<a href="https://agentmods.dev/skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty"><img src="https://agentmods.dev/badge/skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty/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 api-fuzzing-bug-bounty

Your own site · 80×15
<a href="https://agentmods.dev/skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty"><img src="https://agentmods.dev/badge/skills/sickn33/agentic-awesome-skills/api-fuzzing-bug-bounty.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,963 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket warn 1 Aug 2026
  • Snyk fail 1 Aug 2026
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 4 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 156
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 313
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Tool Misuse · line 183
    Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
    Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
  • medium Data Exfiltration · line 435
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
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 $0.00048 $0.02963
Opus 5 $0.00024 $0.01482
Sonnet 5 $0.00010 $0.00593
Haiku 4.5 $0.00005 $0.00296

Measured 7d ago against content hash 9b83b636b81c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

api-fuzzing-bug-bounty scanned grade A 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 7d ago.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -X POST https://target.com/graphql \
Origin

Copies of this mod

8 near-identical copies found in the catalogue:

plugins/agentic-awesome-skills-claude/skills/api-fuzzing-bug-bounty/SKILL.md · 454 lines

How it starts

The opening of the file, as written. The whole thing — 454 lines — stays where its author put it; the contents beside it link to each section on GitHub.

⚠️ AUTHORIZED USE ONLY This skill is for educational purposes or authorized security assessments only. You must have explicit, written permission from the system owner before using this tool. Misuse of this tool is illegal and strictly prohibited.

Mandatory confirmation gate Before running any command that probes, exploits, changes, persists on, extracts data from, or attempts credential access against a target:

  1. Ask the user to state the exact target URL, IP, account, or resource.
  2. Ask the user to confirm written authorization and the permitted scope.
  3. Show the exact command(s) and explain their expected effect.
  4. Wait for explicit confirmation in the current conversation.

Without that confirmation, remain read-only and provide defensive guidance only. Prefer a sandbox, disposable VM, or controlled lab.

AUTHORIZED USE ONLY: Use this skill only for authorized security assessments, defensive validation, or controlled educational environments.

API Fuzzing for Bug Bounty

Purpose

Provide comprehensive techniques for testing REST, SOAP, and GraphQL APIs during bug bounty hunting and penetration testing engagements. Covers vulnerability discovery, authentication bypass, IDOR exploitation, and API-specific attack vectors.

Inputs/Prerequisites

  • Burp Suite or similar proxy tool
  • API wordlists (SecLists, api_wordlist)
  • Understanding of REST/GraphQL/SOAP protocols
  • Python for scripting
  • Target API endpoints and documentation (if available)

Outputs/Deliverables

  • Identified API vulnerabilities
  • IDOR exploitation proofs
  • Authentication bypass techniques
  • SQL injection points
  • Unauthorized data access documentation

API Types Overview

Type Protocol Data Format Structure
SOAP HTTP XML Header + Body
REST HTTP JSON/XML/URL Defined endpoints
GraphQL HTTP Custom Query Single endpoint

Core Workflow

Step 1: API Reconnaissance

Read the full file on GitHub · 454 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. 7d ago First seen · 454 lines · 48 tokens per session scan A 9b83b636b81c

Subscribe to this mod's changes

api-fuzzing-bug-bounty is a skill published in the GitHub repository sickn33/agentic-awesome-skills (46,288 stars, last pushed 3d ago), licensed MIT. It adds 48 tokens to every session and 2,963 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-05.