0. Overview
Web applications actively facilitate business operations, allowing businesses to interact with customers, streamline processes, and deliver crucial services over the internet. Cyber attackers often focus on these applications because of their online availability and the potential to exploit design or implementation flaws.
Organizations, particularly those that have never undergone a penetration test, face significant security risks linked web applications. Access control is just one common vulnerability, where applications insufficiently protect access to resources. This blog explores Access Control Vulnerabilities, providing insights into their potential impacts and strategies for mitigation.
1. What are Access Control Vulnerabilities?
Access control vulnerabilities occur when the mechanisms governing access to resources or actions within a system or application are weak or improperly implemented. Such vulnerabilities enable unauthorized users to gain access to sensitive data, functionalities, or system resources due to improper or ineffective access control measures.
2. How Do Access Control Vulnerabilities Happen?
Flaws in software or systems can lead to access control vulnerabilities, allowing individuals to bypass restrictions and access unauthorized data or perform prohibited actions. These flaws may result from bugs in the software, misconfigurations, or even intentional backdoors left by developers.
These vulnerabilities stem from various issues, including such as improper authentication, insufficient authorization checks, misconfigurations, insecure direct object references (IDOR), weaknesses in session management, and inadequate logging and monitoring.
3. Exploiting Access Control
In a simple and insecure application, every user has access to an admin section where passwords are stored in cleartext. In this scenario, we already have login credentials for one user, Eru, with the password: ”password1.”
Login page for the application
User details for Eru’s activity
Further exploration using standard tools reveals the existence of a hint in the robots.txt file, suggesting that something may exist at the /admin location.
Zap output from an Active Scan
Discovery of robots.txt
4. How to Prevent Access Control Vulnerabilities
In order to prevent access control vulnerabilities, it’s crucial to implement security measures early in the Software Development Life Cycle (SDLC).
Deny by Default/Enforce Least Privilege
Follow the principle of justifying specific permissions rather than granting them by default. Only grant full access to resources intended to be publicly accessible; deny access to all others by default.
In addition, assign users the minimum privileges necessary to perform their job duties. Determine least privilege during the design phase, constructing the application from the ground up with security in mind, and then conduct periodic testing.
Utilize a logical access control policy or worksheet to keep organized.
Unify Access Controls
Implement a single, application-wide mechanism for controlling access. This centralized approach ensures consistency in enforcing access rules throughout the entire application. Develop and integrate this mechanism during the design phase of the application, and consistently test and update it to ensure it effectively controls access to resources.
Audit and Test
Regularly audit and test for access control vulnerabilities. This should be done at least yearly, if not quarterly.
At TCM Security, we work to collaborate with your team to test these preventative measures. More information can be found on our website.
Conclusion
Access control vulnerabilities represent a critical threat to the security of digital systems and data. These vulnerabilities stem from various factors like flawed software, misconfigurations, or human error. The repercussions can be severe, ranging from unauthorized access to sensitive information to complete system compromise.
Addressing access control vulnerabilities requires a multifaceted strategy. This includes robust software development practices, thorough security testing, regular audits of access controls, and ongoing user education. By implementing these measures, organizations can significantly reduce the risk of unauthorized access and safeguard their assets.
Additional Resources:
More information about access controls can be found in the TCM Security Academy. Check out these course in particular if you want to learn more:
- Practical Bug Bounty – Authentication and Authorization Attacks section
- Practical Ethical Hacking Course – Find & Exploit Common Web Vulnerabilities
- Practical API Hacking – Attacking Authorization section
About the Author: Angela Brown
As a versatile cybersecurity professional, Ang (d1r7b46) currently serves as an Offensive Security Engineer at TCM Security. Prior to joining TCM, Ang held roles as a DFIR Team Lead and Security Consultant. With a specialization in Open Source Intelligence (OSINT), she dedicates her expertise to researching and combating scams.
Beyond her technical proficiency, Ang actively contributes to community initiatives, particularly within cybersecurity-focused Discord servers. Ang holds a Bachelors of Business Administration, as well as the PNPT and several cloud certifications.
About TCM Security
TCM Security is a veteran-owned, cybersecurity services and education company founded in Charlotte, NC. Our services division has the mission of protecting people, sensitive data, and systems. With decades of combined experience, thousands of hours of practice, and core values from our time in service, we use our skill set to secure your environment. The TCM Security Academy is an educational platform dedicated to providing affordable, top-notch cybersecurity training to our individual students and corporate clients including both self-paced and instructor-led online courses as well as custom training solutions. We also provide several vendor-agnostic, practical hands-on certification exams to ensure proven job-ready skills to prospective employers.
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