Broken Access Control: How to Test Permissions in an Application

Permissions Model

In Broken Access Control testing, identity and authorization are two different questions: who is the client, and what are they allowed to do to the resource. Roles, Claims, Session, Object ownership, and changes throughout the lifecycle are checked, not just that the user is 'logged in'.

A test matrix includes an anonymous user, a regular user, an object owner, another user, and an administrator. For each action, the Response and server-side impact are compared. Changing an identifier or Header is only a testing means; the evidence is that the server allowed or denied an action contrary to policy.

Horizontal vs. Vertical

To understand the difference in the context of Broken Access Control testing, it's important to compare goals, not just tools. One option provides breadth or speed, and another provides deep validation or context. The correct choice depends on the question: Is discovery, investigation, impact proof, containment, or reporting required?

A professional comparison table should include at least: input type, certainty level, operational cost, potential impact, limitations, and required follow-up. In case of doubt, use the least intrusive approach and add a complementary source instead of drawing too broad a conclusion.

Testing Endpoints and Actions

The topic 'Testing Endpoints and Actions' is a central part of working on Broken Access Control testing. It is recommended to break it down into three questions: what is the input, what decision do you want to make, and what evidence is sufficient to justify it. These questions prevent automatic tool use without understanding the goal.

In practice, write down the role matrix, object identifiers, server-side authorization, horizontal/vertical access, response differences, compare to expected behavior, and define at least one Pivot. The result should be verifiable by another analyst, including limitations and next steps.

Evidence and Risk

The topic 'Evidence and Risk' is a central part of working on Broken Access Control testing. It is recommended to break it down into three questions: what is the input, what decision do you want to make, and what evidence is sufficient to justify it. These questions prevent automatic tool use without understanding the goal.

In practice, write down the role matrix, object identifiers, server-side authorization, horizontal/vertical access, response differences, compare to expected behavior, and define at least one Pivot. The result should be verifiable by another analyst, including limitations and next steps.

Remediation and Retest

Professional Broken Access Control testing begins with success and failure conditions. Define a positive Case, a negative Case, a boundary Case, and similar legitimate activity. This allows identifying both False Negatives and False Positives.

In an authorized environment, a minimal action that proves the claim without causing harm is used. Input, Output, time, and version are saved, and after remediation, a Retest is performed in the same scenario, and Regression on nearby functions is also checked.

Unique Test Focus Areas

On this topic, it is recommended to build a focused evidence map in advance. The main test focus areas are: role matrix, object identifiers, server-side authorization, horizontal/vertical access, response differences, audit logs. The list is not an automatic Checklist; each item is chosen because it can link an entity, action, and time or explain legitimate behavior.

• role matrix: Define the expected value, what would be considered an anomaly, and what additional source would confirm the finding.
• object identifiers: Define the expected value, what would be considered an anomaly, and what additional source would confirm the finding.
• server-side authorization: Define the expected value, what would be considered an anomaly, and what additional source would confirm the finding.
• horizontal/vertical access: Define the expected value, what would be considered an anomaly, and what additional source would confirm the finding.
• response differences: Define the expected value, what would be considered an anomaly, and what additional source would confirm the finding.
• audit logs: Define the expected value, what would be considered an anomaly, and what additional source would confirm the finding.

When one of the focus areas is unavailable, the gap must be documented, and an alternative chosen. For example, if a Process identifier is unstable, time, Host, User, and Parent can be used; if a Payload is encrypted, Metadata, volume, frequency, and TLS/DNS context are used.

Recommended Workflow

1. Define Scope and one working question regarding Broken Access Control testing.
2. List the data sources and required evidence: role matrix, object identifiers, server-side authorization, horizontal/vertical access.
3. Create a short Baseline of normal behavior or expected outcome.
4. Perform the minimal test in a lab environment and save time, input, and output.
5. Build a Timeline or comparison table and separate fact from interpretation.
6. Perform a Pivot to an additional source to confirm or refute the initial explanation.
7. Summarize the decision, limitations, recommended action, and Retest criteria.

Practical Scenario

The chosen scenario is a permissions matrix for a lab application. The purpose of the exercise is not to prove attack capability, but to practice safe collection, comparison, and documentation. Before starting, define mock data, a time window, and an expected outcome.

At the end of the exercise, a product that another analyst or tester can review should be submitted: a screenshot or Export of the evidence, a short Timeline, an initial assumption, corroborating evidence, a limitation, and a recommendation. When there is insufficient evidence, the correct conclusion is that the scenario was not proven.

Practical Checklist

• ✓Check and document: Role and session.
• ✓Check and document: Endpoint and method.
• ✓Check and document: Request/Response.
• ✓Check and document: Object identifier.
• ✓Check and document: Server-side effect.
• ✓Check and document: Control expected and remediation.
• ✓Specify Time zone, tool version, and collection time.
• ✓Save the raw data before filtering or modification.
• ✓Write what the finding proves and what is still unknown.
• ✓Define owner and next action with a due date.

Common Mistakes

• Checking only Status code.
• Relying on Client-side changes.
• Using a dangerous Payload.
• Not checking different Roles.
• Ignoring business logic.
• Reporting without clean Request/Response.

Summary and CTA

Broken Access Control: How to Test Permissions in an Application is a topic that connects technical knowledge with work discipline. Start with a question, collect only relevant evidence, maintain context and time, and choose an action that can be justified and re-tested.

In HPI's Cybersecurity & AI track, these principles are practiced using systems, logs, and labs. A natural continuation is to proceed to the linked articles, perform the lab exercise, and save the output as part of a professional portfolio.

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