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pentest-race-conditions

Concurrency exploitation — race conditions, TOCTOU vulnerabilities, and parallel request abuse in web applications.

Skill by jd-opensource

IndexedApache-2.0★ 315
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Install

Works with Claude Code, Claude apps, Codex, Cursor, Gemini CLI, GitHub Copilot, VS Code, OpenCode, Goose, Windsurf. Read the repository before you give any tool access to your data.

npx agentmarket install skill/jd-opensource-pentest-race-conditions

Asks which of your tools to add it to (Claude Code, Codex, Cursor, VS Code, Windsurf, Gemini CLI, Claude Desktop) and shows the change first. See https://agentmart.dev/cli.

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About

Concurrency exploitation — race conditions, TOCTOU vulnerabilities, and parallel request abuse in web applications.

Use cases: security

No reviews yet. Installed it? Reviews come from verified installers only. How reviews work

Permissions

What this skill can do and what it asks for, from its SKILL.md. Checked Oct 25, 2026.

Tools
No tools found
Secrets
None asked for
Install scripts
None found

Network hosts it talks to 1

  • codeload.github.com · found in install command

Files it touches

  • ~/.claude/skills/pentest-race-conditions

What's inside

Skill name
pentest-race-conditions
Description
Concurrency exploitation — race conditions, TOCTOU vulnerabilities, and parallel request abuse in web applications.
License
Apache-2.0
Instructions
43 lines in SKILL.md · view on GitHub

Before installing

  • Instructions call the network

Files (3)

  • SKILL.md
  • tools.md · references/
  • workflows.md · references/

SKILL.md (first lines)

# Pentest Race Conditions

## Purpose
Exploit applications that fail to handle concurrent requests atomically — enabling double-spend, limit bypass, privilege escalation through parallel requests. Absent from standard WSTG categories but critical in real-world assessments.

## Prerequisites

### Authorization Requirements
- **Written authorization** with explicit scope for concurrency testing
- **Test accounts** with balances, quotas, or limited-use resources
- **Rollback plan** for financial or state-mutating operations
- **Rate limit awareness** — confirm acceptable burst volume with target owner

### Environment Setup
- Burp Suite Professional with Turbo Intruder extension
- Python 3.x with asyncio/aiohttp for parallel request scripting
- GNU parallel or xargs for shell-based concurrency
- Multiple authenticated sessions (separate cookies/tokens)

## Core Workflow
1. **Target Identification**: Identify race-prone operations — balance transfers, coupon redemption, inventory purchase, vote/like systems, token generation, file operations.
2. **Single-Endpoint Races**: Send N identical requests simultaneously to bypass "one per user" limits, duplicate transactions (limit-overrun).
3. **Multi-Endpoint TOCTOU**: Exploit time gap between check and use — validate coupon then apply coupon, check balance then debit.
4. **Session-Level Races**: Parallel password change + session refresh, simultaneous role change + action execution.
5. **Database-Level Races**: Exploit missing row-level locks, test optimistic vs pessimistic concurrency, trigger deadlocks.
6. **Timing Synchronization**: Use single-packet attack technique (Turbo Intruder) to synchronize requests within microseconds.
7. **Impact Documentation**: Document financial/operational impact with precise reproduction steps and timing requirements.

## Tool Categories

| Category | Tools | Purpose |
|----------|-------|---------|
| Timing Attacks | Turbo Intruder, race-the-web | Microsecond-synchronized parallel requests |
| Async Scripting | Python asyncio/aiohttp, httpx | Custom race condition scripts |
| Shell Concurrency | GNU parallel, xargs, curl | Quick parallel request testing |
| Proxy Analysis | Burp Suite Repeater | Request replay and timing observation |
| Database Monitoring | pg_stat_activity, SHOW PROCESSLIST | Observe lock contention and deadlocks |

## References
- `references/tools.md` - Tool function signatures and parameters
- `references/workflows.md` - Attack pattern definitions and test vectors

From jd-opensource/JoySafeter, Apache-2.0.

More from jd-opensource/JoySafeter

Signals

Stars
315
Forks
56
Open issues
17
Last commit (this folder)
Feb 11, 2026 (8 months ago)
Last release
Jul 2, 2026 (3 months ago)

From GitHub (fetched Oct 24, 2026).

Details

License
Apache-2.0
First seen
Oct 24, 2026
Last checked
Oct 24, 2026

More from jd-opensource

Cite this page

pentest-race-conditions skill. Agent Mart. https://agentmart.dev/skills/jd-opensource-pentest-race-conditions (last updated 2026-10-24)