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.
git clone --depth 1 https://github.com/akashrpatil/awesome-offensive-security-skillsnpx agentmods add skills/akashrpatil/awesome-offensive-security-skills/race-condition-toctou-exploitationWrote 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.
[](https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/race-condition-toctou-exploitation)<a href="https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/race-condition-toctou-exploitation"><img src="https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/race-condition-toctou-exploitation/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.
<a href="https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/race-condition-toctou-exploitation"><img src="https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/race-condition-toctou-exploitation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00072 | $0.01996 |
| Opus 5 | $0.00036 | $0.00998 |
| Sonnet 5 | $0.00014 | $0.00399 |
| Haiku 4.5 | $0.00007 | $0.00200 |
Grade A, and why
race-condition-toctou-exploitation 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 8d 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.
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.
How it starts
The opening of the file, as written. The whole thing — 184 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Race Condition (TOCTOU) Exploitation
When to Use
- When testing critical business logic that updates a finite state (balances, stock/inventory, one-time coupons, likes/votes).
- When a single action should be permitted once per user, but you suspect the back-end database locking mechanism (e.g., ACID transactions or Mutexes) is flawed.
- When an application executes a "Check" (Do they have enough money?) followed by a delayed "Use" (Deduct the money). Note: This split-second window between check and use is the target.
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: Identifying Race Windows
# Concept: You need to identify endpoints that perform sequence-dependent logic.
# A classic example: Applying a $50 discount code to a cart.
# The Flawed Backend Logic (Conceptual):
# 1. Check if 'DISCOUNT_CODE' is unused for User A. (Time of Check)
# 2. Add $50 discount to User A's cart.
# 3. Mark 'DISCOUNT_CODE' as used for User A. (Time of Use)
# Goal: Send 20 concurrent requests. If requests 2-20 hit the server BEFORE
# request 1 marks the code as used in step 3, the server will apply the discount 20 times.
Phase 2: Single-Packet Attack (Burp Suite Pro)
# Concept: Network latency and jitter often ruin race conditions because your
# 20 requests arrive at slightly different milliseconds.
# Modern technique: HTTP/2 Single-Packet Attack (sending multiple requests within a single TCP packet).
# 1. Send the target request to Burp Repeater (e.g., POST /api/apply_coupon).
# 2. Group the requests:
# - Duplicate the tab 20 times.
# - Select all 20 tabs, right-click -> "Add tab to group" -> Create new group.
# 3. Execution:
# - Click the dropdown arrow next to the "Send" button.
# - Select "Send group in parallel (last-byte sync)".
# - Click Send.
# 4. Analysis:
# If you receive multiple "200 OK - Coupon Applied" responses, you successfully raced the endpoint.
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.
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.
- 8d ago First seen · 184 lines · 72 tokens per session scan A 3bdb33ed0de6
race-condition-toctou-exploitation 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 72 tokens to every session and 1,996 once invoked, about $0.0004 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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