A1 Broken Access Control: Seeing is Believing (with Examples)

A Critical Web Application Vulnerability

As you highlighted, Broken Access Control (BAC) stands as the top vulnerability in the OWASP Top 10 list for a reason. It involves unauthorised users accessing data or functionalities they shouldn’t have. This can have severe consequences, including:

  • Data breaches: Sensitive information like user data, financial records, or confidential business documents can be compromised.
  • System manipulation: Attackers could modify or delete critical data, disrupting operations or causing financial losses.
  • Privilege escalation: Unauthorized access could be used as a stepping stone to gain higher privileges and further compromise the system.

So, what are the standard ways BAC vulnerabilities arise? Here are some examples:

  • Incorrect access control checks: Applications may fail to properly verify user permissions before granting access to resources.
  • Exploiting session vulnerabilities: Attackers could hijack or steal session cookies to impersonate legitimate users.
  • Parameter manipulation: Modifying parameters in URLs or forms can sometimes bypass access control mechanisms.
  • Misconfiguration: Security settings on servers, databases, or applications may be misconfigured, leading to vulnerabilities.

However, there are ways to mitigate this risk and prevent BAC vulnerabilities:

  • Principle of least privilege: Implement the principle of least privilege, granting users only the minimum access needed for their tasks.
  • Secure authentication and authorisation: Use robust authentication mechanisms and enforce proper access control checks.
  • Input validation: Validate all user input to prevent manipulation of parameters and SQL injection attacks.
  • Regular security testing: Conduct vulnerability scans, penetration testing, and code reviews to identify and fix BAC vulnerabilities.
  • Keeping software updated: Promptly apply security patches and updates to software and libraries.

By taking these steps, organisations can significantly reduce the risk of BAC vulnerabilities and protect their sensitive information and systems.

Broken Access Control (BAC) can be a complex vulnerability, but understanding its real-world impact can be eye-opening. Let’s dive into some concrete examples to illustrate how unauthorised access can occur and the potential consequences:

Scenario 1: E-commerce Shopping Spree Gone Wrong

Imagine you’re an online shopper browsing a clothing website. You add some items to your cart and proceed to checkout. During checkout, a website access control system bug allows you to modify another customer’s order details. Suddenly, you see their name, address, and credit card information! This is a classic example of horizontal access control vulnerability, where one user gains access to another user’s data.

Impact: The compromised customer’s financial information is exposed, putting them at risk of identity theft and fraudulent charges. The e-commerce website faces a data breach, damaging its reputation and potentially facing legal repercussions.

Scenario 2: Hospital Record Hijinks

Imagine a nurse’s station computer accessing patient records in a hospital setting. Due to a weak authentication mechanism, an unauthorised person posing as a nurse gains access to the system. They can now browse sensitive patient information, including medical history, diagnoses, and medications.

Impact: Patient privacy is violated, potentially leading to emotional distress and even harm if the attacker misuses the information. The hospital faces severe HIPAA violations and reputational damage.

Scenario 3: Admin Panel Peek-a-Boo

Picture a website administrator accidentally leaving their login credentials exposed in plain text on a public code repository. An attacker discovers this vulnerability and uses the credentials to access the website’s admin panel. Now, they have complete control over the website, including the ability to modify content, add new users, and even delete data.

Impact: The website can be defaced or used to spread malware. Sensitive data can be stolen or deleted, causing disruption and financial losses. The website owner’s reputation is tarnished, and they may face legal action.

These are just a few examples of how BAC vulnerabilities can play out in real-world scenarios. The consequences can range from inconvenient to catastrophic, highlighting the importance of robust access control measures in any system dealing with sensitive information or functionalities.

Remember, preventing BAC is not just about technology; it’s also about security awareness and best practices. Organisations can significantly reduce the risk of unauthorised access and protect their valuable assets by educating users, developers, and administrators about the dangers and implementing adequate security controls.

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