bola-idor

bola-idor is a skill for Claude Code, Codex from ShulkwiSEC/bb-huge. It costs 107 tokens per session (1,863 once invoked), scanned A, original, MIT.

A security-testing guide for finding broken object-level authorization, also called BOLA or IDOR, in web applications and APIs. The flaw lets one user access another user's object by replacing an identifier.

In plain words
What is it for?
Use it to test user-scoped resources, object IDs in URLs and request bodies, older API versions, and endpoints for exports, downloads, or sharing.
Why use it?
It helps find missing ownership checks that automated scanners may overlook. Such checks can prevent unauthorized reading, editing, deletion, downloads, or sharing of records.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code.

Good fit Use it to test user-scoped resources, object IDs in URLs and request bodies, older API versions, and endpoints for exports, downloads, or sharing.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/shulkwisec/bb-huge/bola-idor
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 ShulkwiSEC/bb-huge --skill bola-idor
Clone the repo
git clone --depth 1 https://github.com/ShulkwiSEC/bb-huge

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 bola-idor

README.md
[![agentmods](https://agentmods.dev/badge/skills/shulkwisec/bb-huge/bola-idor/github.svg)](https://agentmods.dev/skills/shulkwisec/bb-huge/bola-idor)
Your own site
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/bola-idor"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/bola-idor/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 bola-idor

Your own site · 80×15
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/bola-idor"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/bola-idor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 107 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,863 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.
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 $0.00107 $0.01863
Opus 5 $0.00053 $0.00932
Sonnet 5 $0.00021 $0.00373
Haiku 4.5 $0.00011 $0.00186

Measured 6d ago against content hash 01c60b97fb2b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

bola-idor 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 6d 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.

compatibility: Designed for Claude Code. Burp Suite (Autorize extension) or curl recommended.
skills/curated/bola-idor/SKILL.md · 155 lines

How it starts

The opening of the file, as written. The whole thing — 155 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Broken Object Level Authorization (BOLA / IDOR)

What Is Broken and Why

The server accepts a resource identifier from the client and fetches the object without verifying the requesting user owns or has access to it. Authorization is enforced at the route level ("is this user logged in?") but not at the object level ("does this user own object 1042?"). An attacker substitutes their identifier for a victim's to read, modify, or delete resources they should never access. BOLA is consistently the #1 OWASP API Security risk because it is trivial to test and almost always yields high-severity findings.

Key Signals

  • Numeric or sequential IDs in URL path: /api/orders/1042, /users/7/profile
  • UUIDs or hashes in query params or body referencing another user's object
  • Parameters named user_id, account_id, owner_id, ref, target_id, invoice
  • Write operations (PUT/PATCH/DELETE) accepting an object ID
  • Export/download/share endpoints with a resource ID parameter
  • Keywords me or current used as ID aliases — swappable for integer IDs
  • Older API versions still accessible: /v1/, /v2/, /legacy/
  • UUIDs discoverable via public profiles, share links, password reset flows, Wayback Machine

Methodology

  1. Map all object identifiers across the entire app — URLs, query params, request body, cookies, headers.
  2. Create two accounts with distinctive names (e.g. attacker_a, victim_b). Use separate browsers to keep sessions fully isolated. Fully populate the victim account with varied resources and document all encountered IDs. Capture all requests with the victim session.
  3. Replay each request using the attacker token with the victim's object IDs.
  4. Compare responses — same data returned = BOLA confirmed.
  5. Test unauthenticated: remove Authorization header entirely.
  6. Test write operations (PUT/PATCH/DELETE) — impact is higher than reads.
  7. Test indirect references: export endpoints, share links, scheduled jobs, email triggers.
  8. Test less-visible features: auto-save, draft, notification, audit log, attachment endpoints.
  9. Try older API versions (/v1/, /beta/) which often lack access control patches.
  10. For second-order IDOR: store a payload referencing victim's ID, trigger async processing, observe outcome.

Read the full file on GitHub · 155 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. 6d ago First seen · 155 lines · 107 tokens per session scan A 01c60b97fb2b

Subscribe to this mod's changes

bola-idor is a skill published in the GitHub repository ShulkwiSEC/bb-huge (22 stars, last pushed 2mo ago), licensed MIT. It adds 107 tokens to every session and 1,863 once invoked, about $0.0005 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 2026-09-03.

Related

Other skills, from other repositories

hunt-api-misconfig

Hunt API security misconfiguration — mass assignment, prototype pollution, HTTP verb tampering. Mass assignment: send {isadmin:true, role:admin, verified:true} on profile/account/reset endpoints — server blindly applies. JWT signature/crypto forging (alg:none, key confusion, kid/jku) is owned by hunt-jwt-crypto; this…

elementalsouls/Claude-BugHunter · 207 tokens

octopus-architecture

Review system architecture, simplify boundaries, or compare interface designs from repository evidence.

nyldn/claude-octopus · 19 tokens

agenticx-a2a-connector

Guide for using the A2A (Agent-to-Agent) communication protocol in AgenticX including agent discovery, skill invocation, remote agent cards, and distributed agent systems. Use when the user wants agents to communicate with each other, set up distributed agent systems, invoke remote agent skills, or build…

DemonDamon/AgenticX · 73 tokens

agenticx-tool-creator

Guide for creating custom tools in AgenticX including function decorator tools, MCP tool integration, tool registries, and remote tool access. Use when the user wants to create tools for agents, integrate external APIs as tools, build MCP servers, or extend agent capabilities with custom functions.

DemonDamon/AgenticX · 63 tokens

continuum-tools-mcp

Connect MCP servers (Stdio/SSE/StreamableHTTP) to a Continuum agent, configure tool filtering, set up tool-context capture/injection (e.g. sessionid), and read run artifacts (UI widgets, structured tool data). Invoke when the user asks "connect MCP", "filesystem tool", "remote API tool", "auto-capture sessionid"…

shyftlabs/continuum · 94 tokens

pwn-ai-openai

Drive PWN::AI::OpenAI from pwneval.

0dayInc/pwn · 19 tokens