Ultimate API Pentesting Checklist from BreachLock

In the digital world, Application Programming Interfaces (APIs) serve as the linchpin of modern software development and data exchange. These gateways facilitate the exchange of information, making them indispensable for modern software development. However, as organizations increasingly rely on APIs, the need for robust security measures has never been more critical.

Whether you’re a seasoned security professional or a CISO looking to enhance your application’s security, this checklist will serve as your roadmap to safeguard your APIs and ensure the integrity of your application’s ecosystem. Read on to learn more about the API security lifecycle and why API penetration testing matters with the best practices.

Understanding API

An API, short for Application Programming Interface, serves as a critical foundation in the world of software development. It operates as a set of meticulously crafted rules and protocols, acting as a bridge that facilitates seamless communication and interaction between various software applications.

When applications exchange data and functionality through APIs, it’s crucial to protect the integrity, confidentiality, and availability of these interactions. API security entails implementing measures and practices to protect against vulnerabilities, unauthorized access, data breaches, and other potential threats.

Why API Pentesting Matters

APIs are a prime target for cyberattacks due to their critical role in data exchange between different. Leading technology authority Gartner has predicted that API attacks will become the most common vector for cyber threats in 2022, resulting in data breaches for enterprise web applications. However, this prediction is not merely speculative; 2021 witnessed a series of high-profile API breaches, including those affecting Clubhouse, LinkedIn, Parler, and NoxPlayer. These incidents served as stark reminders of the vulnerability of APIs to malicious actors.

A particularly noteworthy case from May involved Peloton, where a Leaky Application Programming Interface unintentionally exposed users’ private data. This incident underscores the urgency of not only comprehending API security but also implementing rigorous security measures to fortify the digital interactions that power your organization.

The consequences of a security breach in an API can be severe:

Data Breaches: Unauthorized access to sensitive data through API vulnerabilities can lead to data leaks and privacy violations.

Financial Loss: Attacks on APIs can result in financial losses, including theft of funds or fraud.

Reputation Damage: Security breaches can severely damage an organization’s reputation and trustworthiness in the eyes of customers and partners.

Regulatory Non-compliance: Failing to secure APIs may lead to non-compliance with data protection regulations such as GDPR, HIPAA, or CCPA, resulting in legal penalties.

To mitigate these risks, organizations must prioritize thorough API penetration testing. This proactive approach allows them to identify and rectify security flaws before malicious actors can exploit them. By doing so, businesses can fortify their digital infrastructure, protect sensitive information, and uphold their reputation and legal compliance in an increasingly interconnected and vulnerable digital landscape.

Lifecycle of API Security Checks

API security is not a one-time affair. It’s a continuous process that requires diligence at every stage of your API’s lifecycle. This includes:

1. Patch Releases: Each time you release a patch, you should conduct a complete API security check. Even seemingly minor updates can introduce new vulnerabilities, so thorough testing is vital.
2. Build Updates: When updating your build, remember that alterations in the source code can inadvertently create new security loopholes. Regular API security checks during these updates are imperative.
3. Source Code Tweaks: Even slight tweaks to the source code demand attention. These innocuous changes can disrupt your API’s delicate balance of security, necessitating yet another round of security checks.

API Pentesting Checklist: 10 Best Practices

An API pentesting security checklist serves as a comprehensive guide outlining essential security measures crucial for bolstering the protection of your APIs against potential cyber threats. This checklist is based on established security standards, such as the OWASP API Security Top 10 Risks and BreachLock’s 2023 Penetration Testing Intelligence Report. According to the BreachLock Report, over 3,000 penetration tests were carried out between 2022 and 2023. The most frequently discovered critical and high-risk vulnerabilities in APIs were domain email spoofing, Apache HTTP server byte range DoS, and sensitive data exposure.

Furthermore, it’s imperative to conduct a thorough API security assessment whenever you release patches, update your codebase, or make even minor adjustments to your source code. These assessments play a vital role in preventing the introduction of new vulnerabilities while addressing existing ones.

1. Authentication and Authorization

Objective: Verify the effectiveness of authentication mechanisms and ensure that only authorized users or applications can access the APIs. Assess if the API enforces proper authorization checks to prevent unauthorized access to resources.
Importance: This control safeguards the API from unauthorized access and data breaches by ensuring that only legitimate users can interact with it.

2. Input Validation and Sanitization

Objective: Examine how the API handles user input. Attempt to exploit common vulnerabilities like SQL injection, NoSQL injection, and other injection attacks to assess whether the API properly validates and sanitizes user-supplied data.
Importance: By scrutinizing input validation, testers identify and mitigate vulnerabilities that could be exploited to manipulate or compromise data.

3. Error Handling and Information Leakage

Objective: Evaluate how the API manages error conditions and whether it provides detailed error messages. Inadequate error handling may lead to information leakage, potentially aiding attackers in understanding the system’s structure and potential attack vectors.

Importance: Proper error handling prevents unintentional information disclosure and strengthens the API’s resilience against potential threats.

4. Session Management

Objective: If the API employs session management, assess the session handling mechanisms for vulnerabilities such as session fixation, session hijacking, and session timeout settings.
Importance: Effective session management ensures that user sessions are secure and not susceptible to exploitation, safeguarding user data and interactions.

5. Data Privacy and Protection

Objective: Review how sensitive data is transmitted and stored within the API. Ensure that sensitive information is encrypted during transmission (using protocols like HTTPS) and adequately protected at rest.
Importance: Protecting sensitive data is paramount to prevent data breaches and maintain the trust of users and stakeholders.

6. Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF)

Objective: Detect vulnerabilities that could enable malicious scripts to be injected into API responses (XSS) or unauthorized actions to be performed on behalf of authenticated users (CSRF).
Importance: Identifying and mitigating XSS and CSRF vulnerabilities enhances the API’s security and shields against common web-based attacks.

7. Business Logic Vulnerabilities

Objective: Examine the API’s business logic to identify flaws that might be exploited for unauthorized access, manipulation, or data exposure.
Importance: Understanding and fortifying the business logic of an API is crucial to prevent unauthorized actions and maintain data integrity.

8. Rate Limiting and Throttling

Objective: Verify if the API has adequate rate-limiting and throttling controls to prevent abuse and denial-of-service (DoS) attacks.
Importance: Rate limiting and throttling protect the API from excessive traffic and malicious overload attempts, ensuring stable and uninterrupted service.

9. Security Misconfigurations

Objective: Review the API’s configuration settings to ensure they are appropriately configured and do not expose sensitive information or create security weaknesses.
Importance: Misconfigurations are a common source of vulnerabilities and addressing them is critical to maintaining a secure API.

10. Logging and Monitoring

Objective: Assess the logging and monitoring capabilities of the API to ensure that security incidents can be detected and responded to promptly.

Importance: Effective logging and monitoring enable organizations to proactively identify and respond to security threats, minimizing potential damage.

Upon completing the penetration testing, the testers provide a comprehensive report detailing the discovered vulnerabilities and recommendations for mitigating the identified risks. This report serves as a roadmap for organizations to bolster the security of their internal APIs and safeguard critical assets from potential attacks. Regular internal API penetration testing is an indispensable component of a robust security program, maintaining a secure and resilient IT infrastructure.

Enhance Your API Security with BreachLock

While this API security checklist covers these vulnerabilities, it’s essential to acknowledge that no checklist can fully shield your API from the ever-evolving tactics and strategies employed by hackers. This limitation arises from the inherent complexity of APIs, where every component can potentially be exploited by malicious actors in some manner.

Moreover, even the most detailed checklist often falls short of effectively addressing the most perilous type of API vulnerabilities – those that may lie within the source code and are not exposed to third-party testing. Without proper scrutiny, adversaries can manipulate legitimate functions of your API to steal data or perform actions beyond their permissions, making this threat extend far beyond traditional hackers.

To address these challenges, organizations require a multifaceted approach to security. This can be achieved by partnering with BreachLock. We are a global leader in Penetration Testing as a Service (PTaaS) and penetration testing services. BreachLock offers automated, AI-powered, and human-delivered solutions in one integrated platform based on a standardized built-in framework that enables consistent and regular benchmarks of attack techniques, security controls, and processes. By creating a standardized framework, BreachLock can deliver enhanced predictability, consistency, and accurate results in real-time, every time.

Schedule a discovery call with one of our pentesting experts to discover how BreachLock can help enhance the security controls of APIs in your organization.