OWASP Top Ten Proactive Controls - C1: Implement Access Control

What is Access Control?

Access Control (or Authorization) is the process of allowing or denying specific requests from a user, program, or process to access a given object. This involves considering a defined policy to determine if the subject has the necessary privileges. It also includes the granting and revoking of these privileges.

What are the threats associated with poorly implemented Access Control?

Data Leaks: Attackers can exploit weak access control policies to access sensitive data that should be restricted.
Exploiting Weak Links: Applications with multiple access control components can be vulnerable if an attacker targets the weakest implementation.
Unsecured Dormant Accounts: Forgotten or inactive accounts can be discovered and used by attackers to gain unauthorized access.
Lack of Default Deny: If access is not explicitly denied by default, attackers could potentially access data through loopholes in the policy.

How should Access Control be designed in an application?

Access control design should be thorough and prioritized from the beginning of development. Two key approaches are:

Role-Based Access Control (RBAC): This model assigns permissions to roles rather than individual users, simplifying management.
Attribute-Based Access Control (ABAC): This offers more granular control by granting or denying access based on attributes of the user, object, and environment.

Why is it crucial to enforce an Access Control check for every request?

Forcing all access requests through a dedicated verification layer ensures consistent application of the access control policy. Utilizing technologies like Java filters helps achieve this by automatically routing requests through the check.

What is the benefit of consolidating access control checks?

Using a single, centralized access control procedure or routine simplifies security management and reduces the risk of inconsistent or flawed implementations. It allows security resources to focus on maintaining and improving one core access control function.

What does "Deny by Default" mean in the context of Access Control?

"Deny by Default" means that all requests are automatically denied unless specifically allowed. This principle minimizes the risk of accidental or unauthorized access. It applies to various scenarios, including new user accounts, added application features, and handling errors or exceptions during access control checks.

What are the benefits of the Principle of Least Privilege and related concepts like JIT and JEA?

The Principle of Least Privilege advocates granting users, programs, or processes only the minimum access rights necessary to perform their tasks. Just-in-Time (JIT) and Just-Enough-Access (JEA) take this further by providing access only when needed and for a limited time, reducing the window of opportunity for misuse.

Why should hard-coding roles in application code be avoided?

Hard-coding roles creates several problems:

Fragility: It's easy to introduce errors or miss checks when roles are scattered throughout the code.
Limited Flexibility: It hinders multi-tenancy, where different clients might require varying access rules.
Difficult Audits: Hard-coded roles complicate security audits and policy verification.
Potential Backdoors: They can be exploited as security vulnerabilities if discovered during audits.