Broken Function Level Authorization (API)
In the context of API security, Broken Function Level Authorization (BFLA) refers to a vulnerability that arises from flaws in how APIs control access to specific functionalities. It means that unauthorized users can perform actions or access data for which they shouldn't have permission.
Here's a breakdown of the critical aspects:
Function Level: An API can offer various functionalities, each potentially requiring different access levels. For example, an API for managing user accounts might have functionalities for creating new users, updating profiles, or deleting accounts.
Authorization: This refers to the security mechanism determining who can access and perform specific functionalities within the API.
Broken: This indicates that the authorization mechanism needs to be fixed and allow unauthorized access to certain functionalities.
How Broken Function Level Authorization Exploits Work:
Attackers can exploit BFLA vulnerabilities in a few ways:
Insecure Coding: Exploiting coding errors or improper configuration in the API's authorization logic. It might allow unauthorized users to bypass access controls and perform actions they shouldn't be able to.
Predictable Patterns: If the API relies on predictable patterns (like sequential IDs or guessable parameters) to differentiate between functionalities, attackers might manipulate these patterns to access unauthorized functions.
Privilege Escalation: In some cases, attackers might exploit BFLA to gain access to functionalities that grant higher privileges within the system, allowing them to perform even more damaging actions.
Consequences of Broken Function Level Authorization:
Broken Function Level Authorization vulnerabilities can have serious consequences, including:
Data Breaches: Attackers might gain access to sensitive data (like user information or financial records) through unauthorized functionalities.
Account Takeover: In some cases, attackers might exploit BFLA to gain control of other users' accounts.
Disruption of Service: Attackers might exploit unauthorized functionalities to disrupt normal API operations or launch denial-of-service attacks.
Preventing Broken Function Level Authorization:
Here are some ways to prevent Broken Function Level Authorization vulnerabilities:
Implement Least Privilege: Only grant users access to the specific functionalities they need for their tasks.
Robust Authorization Checks: Ensure the API verifies user permissions for every functionality they attempt to access.
Regular Testing: Conduct security testing to identify Broken Function Level Authorization vulnerabilities.
Secure Coding Practices: Developers should follow secure coding practices to avoid introducing authorization flaws in the API code.
API Documentation: Clear and concise API documentation that outlines access requirements for each functionality helps developers understand how to interact with the API securely.
By following these practices, you can significantly reduce the risk of broken Function-Level Authorization vulnerabilities and ensure your APIs have robust access controls for each functionality.
Discovery: The Foundation for Secure APIs
Identifying External APIs: ThreatNG excels at discovering external APIs with which your programs interact. You can only address BFLA vulnerabilities if you know the APIs in your attack surface.
EASM and DRP: Building Intelligence
External Threat Monitoring: EASM continuously monitors the external landscape for newly discovered vulnerabilities and potential BFLA threats. This helps you stay informed about evolving attack techniques that exploit weaknesses in the function-level authorization.
Digital Risk Protection: DRP provides valuable intelligence about known BFLA vulnerabilities and best practices for securing access control within APIs. This knowledge empowers you to prioritize security efforts based on the specific APIs.
Collaboration is Key: ThreatNG and Complementary Tools
ThreatNG works seamlessly with other security solutions to create a robust defense against BFLA vulnerabilities. Here's a positive handoff example:
ThreatNG Discovers and Identifies: ThreatNG discovers external APIs and identifies those your programs interact with.
Handoff to API Security Testing Tools: This information is passed on to dedicated API security testing tools, such as SAST (Static Application Security Testing) or DAST (Dynamic Application Security Testing) solutions.
Focused Testing for Functionality and Access: These tools analyze the API, focusing on how it controls access for different functionalities. They can identify weaknesses like missing authorization checks for specific functions or logic that allows unauthorized users to perform privileged actions.
Remediation and Continuous Monitoring: Developers identify and address BFLA vulnerabilities in the API, and ThreatNG's EASM continues monitoring for new threats.
Beyond Functionality and Access: A Holistic Approach
While ThreatNG helps identify APIs based on functionality, a comprehensive approach goes further:
DRP Insights: ThreatNG's DRP can provide insights into specific BFLA vulnerabilities associated with the discovered APIs or the frameworks used to build them. This knowledge empowers security testers to tailor their analysis to address known risks beyond functionality and basic access control checks. For example, DRP might reveal vulnerabilities in popular API frameworks that can lead to BFLA exploits.
Security Champions: ThreatNG can integrate with Secure Development Lifecycle (SDL) tools, fostering a culture of security. Developers become aware of potential BFLA risks and can write code that enforces granular access controls based on functionality and user roles.
A strong security posture relies on collaboration. ThreatNG acts as the initial scout, discovering external APIs. It then works with developers, API security testing tools, and other solutions to create a layered defense that minimizes the risk of BFLA vulnerabilities and ensures your APIs have proper authorization checks for each function. By proactively identifying potential risks and collaborating with other tools, ThreatNG helps you stay ahead of attackers and secure your APIs.
