How to Prevent Broken Access Control?

As more and more services move online, the importance of access control becomes increasingly clear. Access control refers to the processes that limit the ability of unauthorized individuals or entities to access resources, whether those resources are software, data, or physical spaces. Broken access control is one of the most common vulnerabilities in software, and it's also one of the most damaging. In this article, we'll explore what broken access control is, what its consequences can be, and most importantly, how to prevent it.

What is Broken Access Control?

Broken access control refers to a situation in which an attacker is able to access a resource or perform an action that should be restricted. This can happen for a number of reasons. For example, a developer may have inadvertently made a security mistake, or a vulnerability may have been introduced due to a third-party library or service.

There are many different ways in which access control can be broken. For example, an attacker may be able to bypass authentication, gain access to privileged data or resources, or modify data that should be read-only. Broken access control can occur at any level of an application, from the user interface to the back-end data storage.

What are the Consequences of Broken Access Control?

The consequences of broken access control can be severe. In some cases, an attacker may be able to gain full control of a system, steal sensitive data, or delete important information. For example, an attacker might be able to bypass a login screen and gain access to a user's account. Once inside, the attacker could steal sensitive information, modify account settings, or even initiate fraudulent transactions.

In other cases, the damage caused by broken access control may be more subtle. For example, an attacker might be able to gain access to sensitive information that they are not authorized to see, leading to privacy violations or regulatory noncompliance. Broken access control can also lead to reputational damage, loss of customer trust, and other business risks.

How to Prevent Broken Access Control?

Preventing broken access control requires a multi-layered approach that involves careful design, development, and testing. In the following sections, we'll explore some of the key techniques and best practices that can help prevent broken access control.

1. Access Control Design

One of the most important steps in preventing broken access control is to design access control measures that are robust and effective. Access control design should consider the different roles and levels of access that users or entities will need, and ensure that the appropriate restrictions are in place.

For example, it's important to limit access to administrative functions to only those users who need it, and to ensure that access is granted based on the principle of least privilege. This means that users are given only the minimum level of access that they need to perform their job, and no more. This can help prevent situations where a user with too much access accidentally or intentionally causes harm to the system.

2. Authentication and Authorization

Authentication and authorization are two key components of access control. Authentication is the process of verifying a user's identity, while authorization refers to the process of determining whether a user is allowed to perform a particular action or access a particular resource.

To prevent broken access control, it's important to ensure that both authentication and authorization are implemented correctly. Authentication should be implemented using strong and reliable techniques such as multi-factor authentication or biometric authentication. Authorization should be designed to ensure that users are only given access to the resources that they are authorized to access.

3. Input Validation and Output Encoding

Another important technique for preventing broken access control is input validation and output encoding. Input validation refers to the process of checking user input to ensure that it is valid and safe. Output encoding refers to the process of encoding output data to prevent it from being misinterpreted or exploited.

4. Error Handling

Access control errors can occur due to various reasons such as incorrect user inputs, system failures, and unexpected conditions. It's important to implement proper error handling mechanisms to prevent attackers from exploiting such errors to gain unauthorized access. Error messages should not expose sensitive information and should be worded in a clear and simple manner so that users can comprehend them.

5. Access Control Based on Roles

Role-based access control (RBAC) is an access control approach that allocates permissions to individuals based on their organisational role.

This method simplifies access control administration while also lowering the possibility of mistakes or unwanted access.

RBAC assigns each user a set of roles, and each role is coupled with a set of permissions.

This method assures that users only have access to the resources they require to execute their job obligations, while also preventing illegal access to sensitive data and systems. RBAC can also help organizations meet compliance requirements, as it provides a clear audit trail of user activity.

6. Regular Audits and Testing

Regularly auditing and testing access control measures is crucial in preventing broken access control. This includes both internal and external audits, as well as regular penetration testing. An internal audit can identify weaknesses in the system and help address them before they become a problem. External audits can ensure that the system is secure from outside threats.

Penetration testing can simulate an attack on the system to identify vulnerabilities and help improve the security of the access control measures. This can be done by hiring an external security firm to perform the testing or by having an in-house team perform the testing. Regular testing can help identify and fix weaknesses before they are exploited by attackers.


Broken access control is a serious threat to the security of any organization. It allows attackers to gain unauthorized access to sensitive data and systems, potentially leading to data breaches and other security incidents. To prevent broken access control, organizations must implement a comprehensive access control strategy that includes defining and enforcing access control policies, implementing strong authentication and authorization measures, and regularly auditing and testing the system.

By following these best practices, organizations can significantly reduce the risk of broken access control and ensure the security of their sensitive data and systems. However, it's important to keep in mind that security is an ongoing process, and organizations must remain vigilant in monitoring and updating their access control measures to stay ahead of emerging threats.

Updated on: 27-Feb-2023


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