
Broken access control is a distinct vulnerability that is always listed in OWASP Top 10 when it comes to web application security. So as CyberSamir I want to guide you through what this vulnerability is, how attackers exploit it, and what you can do to secure your applications from it.
What is Broken Access Control?
Access control makes sure that users cannot have access to resource or make actions which they have not been given allowance to perform. In this case, if this mechanism is broken then Unauthorized users are allowed access to restricted functionalities or data.
This vulnerability can have severe consequences, such as data breaches, unauthorized changes (or worse, full system compromise).
How does broken access control occur?
Misconfiguration of permissions, or flaws in application logic often cause Broken Access Control. Some common scenarios include:
- Forced Browsing: Attackers manipulate URLs to get to pages you don’t want them to (i.e., /admin or /user/1234).
- Missing Role-Based Access Control (RBAC): User roles are not distinguished within applications so any user with lower privilege can access admin level features.
- IDOR (Insecure Direct Object References): Objects can be referenced predictably, directly by users.
- Unprotected APIs: Applications which authenticate and authorize API calls improperly.
Examples of Broken Access Control
1. Unauthorized Data Access
Scenario: Rather, a user changes its URL in order to see data of another user. For instance:
By changing 123 to say 124, which will give access to someone elses profile.
2. Privilege Escalation
Scenario: Hidden admin functionalities are found by a regular user and they learn they are able to perform admin actions like deleting other users’ accounts.
3. File Upload Vulnerabilities
Scenario: Users upload files without doing any validation, in turn running malicious scripts or exposing directories.
How to Prevent Broken Access Control?
1. Put the role based access control.
Give the permission for a user role (e.g admin, editor, viewer).
By default deny access, and allow access only if explicitly allowed.
2. Announce the availability of Secure Development Practices utility.
Make server side authorization checks for every request.
Best not to rely on client side checks, as they’re easy to work around.
3. Validate User Input and IDs
The IDs on your entities should be unpredictable and non sequential (e.g. UUIDs) to avoid IDOR attacks.
Ensure that the current user has rights to the requested resource.
4. Protect APIs
All API endpoints get authenticated and authorized.
Instead of that, you can use OAuth or an API gateway to safely control access.
5. Regularly test the security.
Automate penetration testing, automated scan to identify vulnerabilities.
Run simulated access control bypass attempts using tools like Burp Suite, OWASP ZAP or with custom scripts.
6. Control Access Attemps
Allow us to log access attempts and detect and flag suspicious activity, e.g. repeated failed attempts to access restricted resources.
Broken Access Control in Real World Implications
Broken Access Control has led to numerous high-profile security incidents:
- Data Breaches: Weak access controls allowed sensitive user data such as personal information and financial records to be exposed.
- System Takeovers: These privilege escalation flaws were found to be exploited by attackers that are able to gain admin access and fully take control of systems.
- Reputation Damage: This legally and financially hit organizations and lost customer trust.
Why Broken Access Control Matters?
High Impact: This vulnerability is often exploited, causing systems to lose data, or worse, be compromised.
Frequent Occurrence: It is one of the most exploited vulnerabilities and proactively mitigating is required.
Compliance Requirements: Since many regulatory standards, such as GDPR and PCI DSS, require strong access control mechanisms, many organisations focus on designing and deploying good strategies for implementing them.
This is a broken Access Control vulnerability that could truly skyrocket, with far reaching consequences if not addressed. If you understand what happens and apply very strong access control, you can decrease the risk of exploitation significantly.
At CyberSamir, we’re passionate about building secure web applications and spreading awareness about best practices in cybersecurity. Remember, securing your applications is not just a technical necessity—it’s a responsibility to your users and their data. Stay informed, stay vigilant, and always prioritize security.
For more insights and tips on web application security, keep following CyberSamir!
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