hunt-mass-assignment

Validates API mass assignment and server-side field allowlist boundaries with evidence-gated probes.

10|3|Updated Aug 10, 2026
One-click install
npx skills add https://github.com/baiqigo/baiqi-redteam-lab --skill hunt-mass-assignment-baiqigo
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: hunt-mass-assignment
Source: https://github.com/baiqigo/baiqi-redteam-lab/tree/main/.agents/skills/hunt-mass-assignment
Command: npx skills add https://github.com/baiqigo/baiqi-redteam-lab --skill hunt-mass-assignment-baiqigo

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? API endpoints that bind unexpected JSON fields to internal model properties can let attackers overwrite sensitive attributes, but confirming this safely requires strict authorization, controlled test objects, and authoritative server-side evidence rather than guesswork from HTTP responses. ## Core Features & Use Cases - Evidence-Gated Validation: Enforces a fixed baseline → single-field probe → post-baseline → authoritative state/audit → evidence workflow so findings rest on server-side proof, not response echoes or HTTP 200s. - Strict Safety Boundaries: Restricts testing to two self-owned identities, a rollback-capable test object, and harmless canary fields, explicitly forbidding role, owner, tenant, payment, email, MFA, or permission fields. - False-Positive Oracle & Routing: Defines what counts as valid proof versus inconclusive signals, and routes related findings to IDOR, HTTP parameter pollution, API misconfiguration, or business-logic workflows. - Use Case: Given an OpenAPI schema showing a PATCH profile endpoint, verify whether an undocumented canary field is persisted server-side for a low-privilege identity, confirmed via an independent authoritative read and then rolled back. ## Quick Start Ask the agent to plan an authorized, evidence-gated mass assignment validation against your own test API endpoint using a harmless canary field.

Frequently Asked Questions about hunt-mass-assignment

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I test an API for mass assignment vulnerabilities?

Send a baseline request with only documented fields, then add one undocumented harmless canary field and check whether the server persists it via an independent authoritative read or audit log. Response echoes or HTTP 200 status alone are not valid proof.

What counts as proof of a mass assignment vulnerability?

Valid proof requires the server to persistently accept a canary field that the allowlist should reject, confirmed by authoritative state or audit logs showing a low-privilege identity wrote it. Client-side caching, silent field dropping, validation errors, or single 2xx responses are inconclusive.

Which fields should never be used in mass assignment testing?

Never probe role, owner, tenant, payment, email, MFA, permission, or real business configuration fields. Testing must use only harmless canary fields on a rollback-capable test object with two self-owned identities.

When should a mass assignment test be stopped?

Stop when testing would touch permissions, object ownership, tenants, funds, credentials, or third-party data, when no independent authoritative read is available, or when changes cannot be rolled back. Related findings route to IDOR, parameter pollution, or business-logic workflows.

Can WAF blocks or CAPTCHAs confirm a mass assignment finding?

No. WAF responses, CAPTCHAs, timeouts, HTTP 200s, field echoes, and client-side state are all classified as inconclusive signals. Only server-side authoritative state or audit evidence can confirm the vulnerability.