hunt-business-logic

hunt-business-logic is a skill for Claude Code, Codex from uphiago/recon-skills. It costs 119 tokens per session (5,007 once invoked), scanned D, original, MIT.

A security-testing guide for flaws in how an application enforces its business rules. These bugs make it possible to manipulate prices, quantities, discounts, verification steps, subscriptions, or permissions without breaking the underlying software.

In plain words
What is it for?
Use it to test checkout, payments, coupons, subscriptions, referrals, verification flows, webhooks, and internal endpoints.
Why use it?
It helps find cases where the application trusts user-controlled values or handles real-world transactions incorrectly.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it to test checkout, payments, coupons, subscriptions, referrals, verification flows, webhooks, and internal endpoints.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/uphiago/recon-skills/hunt-business-logic
About the project

Recon Skills is a pack of security-testing skills covering reconnaissance, web applications, APIs, authentication, vulnerability validation, cloud infrastructure, and reporting. Security professionals use it for authorized assessments of systems they own or have written permission to test. The catalogue entries are individual skills from the pack.

uphiago/recon-skills · 1,254 stars · on GitHub · hiago.sh

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 uphiago/recon-skills --skill hunt-business-logic
Clone the repo
git clone --depth 1 https://github.com/uphiago/recon-skills

Made for: Claude Code, Codex.

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 hunt-business-logic

README.md
[![agentmods](https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-business-logic/github.svg)](https://agentmods.dev/skills/uphiago/recon-skills/hunt-business-logic)
Your own site
<a href="https://agentmods.dev/skills/uphiago/recon-skills/hunt-business-logic"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-business-logic/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 hunt-business-logic

Your own site · 80×15
<a href="https://agentmods.dev/skills/uphiago/recon-skills/hunt-business-logic"><img src="https://agentmods.dev/badge/skills/uphiago/recon-skills/hunt-business-logic.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 119 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,007 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 3 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 $0.00119 $0.05007
Opus 5 $0.00060 $0.02504
Sonnet 5 $0.00024 $0.01001
Haiku 4.5 $0.00012 $0.00501

Measured 8d ago against content hash 64c017c5ca77, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade D, and why

hunt-business-logic scanned grade D with 3 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

curl --max-time 30 --connect-timeout 10 -s -X POST "https://httpbin.org/post" -H "Content-Type: application/json" -d '{"quantity":-1,"price":0}' | python3 -m json.tool 2>/dev/null | grep -q "quantity" && echo "PASS" || e

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl --max-time 30 --connect-timeout 10 -s -X POST "https://httpbin.org/post" -H "Content-Type: application/json" -d '{"quantity":-1,"price":0}' | python3 -m json.tool 2>/dev/null | grep -q "quantity" && echo "PASS" || e

Makes network callslowCapability

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

curl --max-time 30 --connect-timeout 10 -s -X POST https://target.com/api/subscribe \
redteam/hunt-business-logic/SKILL.md · 315 lines

How it starts

The opening of the file, as written. The whole thing — 315 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Crown Jewel Targets

Business logic vulnerabilities pay highest in platforms where financial transactions, identity verification, and access controls intersect with real-world consequences. The richest targets are:

  • E-commerce & payment platforms (Valve/Steam, Shopify) — payment flow manipulation, free goods, price tampering
  • Marketplace & gig economy apps (Airbnb, Uber) — identity/verification bypass enabling fraud or unsafe interactions
  • SaaS with tiered access (Mozilla Monitor) — bypassing verification to unlock monitoring features without entitlement
  • High-traffic consumer apps (Snapchat, Yelp) — rate-limit bypass enabling spam, enumeration, or abuse at scale

Asset types that pay: checkout flows, subscription endpoints, callback/verification systems, webhook handlers, employee/internal portals exposed to the internet, and any endpoint that trusts client-supplied data to make authorization decisions.


Attack Surface Signals

URL patterns to watch:

  • /checkout, /order, /subscribe, /payment, /verify, /confirm, /callback
  • /internal, /employee, /summit, /staff, /admin — internal pages accidentally public
  • /api/v*/payment, /api/v*/notify, /webhook — payment provider callbacks
  • Endpoints accepting X-Forwarded-For, X-Real-IP, CF-Connecting-IP headers

Response/header signals:

  • Set-Cookie with unvalidated session state tied to cart or order data
  • Payment provider names in responses: Smart2Pay, Stripe, PayPal, Braintree
  • Redirect chains through third-party payment pages (in-flight data opportunity)
  • 200 OK on subscription/verification endpoints with no CAPTCHA or token

JS patterns:

  • Hardcoded internal URLs in frontend bundles (/employee/, /staff/, /internal/)
  • Client-side price calculation before server submission
  • Verification logic that only checks on the frontend (if (verified) { ... })
  • fetch('/api/subscribe', { method: 'POST', body: ... }) with no anti-CSRF token or rate-limit token

Read the full file on GitHub · 315 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. 8d ago First seen · 315 lines · 119 tokens per session scan D 64c017c5ca77

Subscribe to this mod's changes

hunt-business-logic is a skill published in the GitHub repository uphiago/recon-skills (1,254 stars, last pushed 10d ago), licensed MIT. It adds 119 tokens to every session and 5,007 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it D with 3 findings (sends data to an external url, downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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