AuthorizationSample Research WriteupOWASP Top 10 - A01:2021 Broken Access Control

Methodical Matrix-Driven Authorization Testing for Complex Web Applications

Published: 2026-01-208 min readAuthor: MASKNODS

A structured methodology for systematically uncovering horizontal and vertical privilege escalation across role-based access control (RBAC) surfaces.

#RBAC#Privilege Escalation#Methodology#Testing Matrix#Burp Suite

01.Overview & Architectural Context

Access control flaws are notoriously difficult for automated dynamic scanners to detect because determining whether a specific user should access a specific resource requires semantic domain context. A methodical testing matrix is essential to consistently uncover subtle authorization defects.

02.Attack Vector & Proof of Concept

Vertical escalation involves a low-privilege user executing administrative actions. Horizontal escalation involves an authenticated user accessing or altering identical-tier data belonging to another user. Both vulnerabilities frequently emerge in multi-tenant SaaS dashboards.

By establishing multiple authenticated test personas (Super Admin, Organization Admin, Member, Read-Only, and Unauthenticated) and capturing request baselines, researchers can execute state-differential fuzzing against internal APIs.

HTTP Request Transcript:

HTTP Request Payload

POST /api/v1/organizations/corp-beta/members/invite HTTP/1.1
Host: dashboard.saas-platform.com
Authorization: Bearer [MEMBER_ROLE_JWT]
Content-Type: application/json

{
  "email": "attacker@external-domain.com",
  "assigned_role": "billing_administrator"
}

HTTP Response Transcript:

HTTP Response Payload

HTTP/1.1 201 Created
Content-Type: application/json

{
  "status": "invited",
  "invitation_id": "inv_9041b3",
  "role": "billing_administrator"
}

03.Source Code Analysis

Role-Permission Matrix Specification Example

{
  "roles": ["SuperAdmin", "OrgAdmin", "Member", "Auditor"],
  "endpoints": [
    {
      "path": "/api/v1/org/{id}/settings",
      "method": "PATCH",
      "expectedAllowed": ["SuperAdmin", "OrgAdmin"],
      "testedOutcomes": {
        "Member": 403,
        "Auditor": 403,
        "Unauthenticated": 401
      }
    }
  ]
}

04.Impact & Risk Assessment

Severity Assessment

Unauthorized data modification, administrative takeover of enterprise tenant accounts, and unauthorized license tier unlocks.

05.Remediation & Engineering Mitigations

Centralize authorization enforcement in dedicated middleware or gateway interceptors rather than scattered route handlers.
Deny access by default; explicitly require permission checks for all state-changing and data-retrieval routes.
Audit all hidden or frontend-suppressed API endpoints for missing server-side authorization checks.