Broken Access Control In-Depth

Articulating the term “broken access” in terms of security, along with its manifestations, and mitigation strategies.

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Broken access control is a security vulnerability that occurs when the access controls implemented by an application are not working as intended, allowing unauthorized access to sensitive information or functionality. This vulnerability can have severe consequences, such as data theft, modification, or destruction, and compromise the confidentiality, integrity, and availability of the system. Due to its impacts it ranks number 1 on the OWASP top 10 list.

In this blog post, we will explore what broken access control is, how it can be exploited, and the best practices to prevent it.

What is Broken Access Control?

Access control is the process of determining who is allowed to access what resources and what operations they are authorized to perform. Access control mechanisms are typically implemented using authentication and authorization techniques, such as username and password authentication, role-based access control, and access control lists.

Broken access control occurs when these mechanisms are not implemented correctly or are not enforced, allowing users to bypass or evade the access controls and gain unauthorized access to sensitive resources or functionality. Broken access control vulnerabilities can occur at different levels of an application, from the client-side to the server-side.

Examples of Broken Access Control Vulnerabilities

1. Insecure Direct Object References (IDOR): This occurs when an application uses user-supplied input (such as an ID parameter) to access an object or resource without proper authorization checks. For example, an attacker may manipulate the ID parameter in a URL to access another user’s private information.
2. Privilege Escalation: This occurs when an attacker gains higher privileges than they are authorized to. For example, an attacker may exploit a vulnerability to gain administrative access to a system, even though they only have standard user privileges.
3. Broken Authentication and Session Management: This occurs when an attacker is able to bypass the authentication and session management mechanisms of an application. For example, an attacker may be able to guess or brute-force a user’s password, or exploit a session fixation vulnerability to take over a user’s session.
4. Access Control Misconfiguration: This occurs when access control rules are not configured or enforced correctly. For example, an attacker may be able to access a sensitive resource or functionality that should only be available to certain users or groups.

How to Prevent Broken Access Control?

Preventing broken access control vulnerabilities requires a combination of good design, coding practices, and testing. The following are some best practices for preventing broken access control:

1. Implement Principle of Least Privilege: Only grant users the minimum permissions necessary to perform their tasks. This limits the impact of any potential breach.
2. Use Role-Based Access Control (RBAC): Define roles that users can be assigned to, each with their own set of permissions, and assign users to roles rather than directly assigning permissions.
3. Use Secure Session Management: Ensure that sessions are properly managed, and session tokens are not vulnerable to attacks such as session fixation or session hijacking.
4. Use Parameterized Queries: Use parameterized queries instead of string concatenation to avoid SQL injection attacks.
5. Perform Input Validation: Validate all user input to ensure it conforms to expected patterns, data types, and values.
6. Conduct Regular Security Testing: Use a combination of automated and manual testing to identify and fix vulnerabilities in your application.
7. Follow Security Best Practices: Follow industry-standard security best practices such as OWASP Top Ten, and keep up-to-date with the latest security trends and threats.

Conclusion

Broken Access Control is a serious web application vulnerability that can have significant consequences for both users and the organization that operates the application. By following the best practices outlined in this blog the organisation can systematically plan the security of application accordingly.

For more knowledge I highly reccommend you to read the guidelines provided by the OWASP on https://owasp.org/www-project-top-ten/

Also have a look at my previous blog on the explaning threat, risk and vulnerability here — https://cyberpands.medium.com/threats-risks-and-vulnerabilities-explained-159916b13f13