Understanding API Breaches: Insights from 'Outliers' and the Complexities of Cybersecurity

Over the last couple of decades in the cybersecurity industry, I have observed how APIs have gained significant importance in modern cloud-based architectures over the past few decades. In fact, they account for over 80% of all web traffic. However, this increased usage has also made APIs vulnerable to cyber threats. 

A closer look reveals that APIs are now one of the most prominent threat vectors in the cybersecurity landscape.

The Importance of API Security

Effective API security testing is a must for modern enterprises, and it requires an approach distinct from the traditional network security measures we typically rely on. 

Given the inherent nature of APIs, breaches can expose massive amounts of sensitive data and provide attackers with the means to quickly access and exfiltrate those datasets. The impact of such breaches can range from costly to catastrophic. But like so many catastrophes, API breaches are rarely the result of a single error.

The 'Outliers' Perspective

Malcolm Gladwell's book, 'Outliers,' identifies that catastrophic events, such as plane crashes, are rarely caused by a single mistake but typically by a series of smaller failures. Similarly, API breaches rarely occur due to isolated oversights or individual errors in security practices. 

Primary and Secondary Threat Vectors

Major API breaches usually involve the exploitation of both primary and secondary threat vectors. 

Take, for example, an internal API that lacks proper authentication. On its own, this might not pose a significant risk. But, if a network configuration change - something as easy as one configuration change or two clicks on public cloud platforms - inadvertently exposes that API to the public, the consequences can be drastic. 

The absence of authentication alone doesn't cause the breach. The interplay between having an internal API without authentication and untracked network configuration changes exposes the API publicly. These threat vectors combine to create a pathway for unauthorized access and can lead to the type of API breaches that make headlines.

APIs as the Backbone of the Modern Web

To understand the magnitude of API breaches, getting a handle on APIs' pivotal role in modern technology is crucial. Mobile apps, IoT devices, cloud-based applications, and enterprise systems all rely on APIs as the communication interface between front-end interfaces and back-end systems. 

The average number of APIs organizations use can range between 15,000 and 25,000, making APIs one of the most significant known software components of an enterprise attack surface - API Security: Market Landscape (Aite-Novarica)

Over 80% of all web traffic now comes from API calls, and we are rapidly approaching the staggering milestone of 1 trillion API endpoints. With such a vast network of APIs, the potential risk of breaches in this domain is unparalleled.

Common API Attack Vectors

Understanding the most prevalent attack vectors is crucial. The Open Web Application Security Project (OWASP) has compiled a list known as the OWASP Top 10, which outlines the most prevalent vulnerabilities and risks:

  • Broken Object-Level Authorization: When an API fails to enforce access controls at the object level properly, attackers might manipulate object identifiers or exploit insufficient authorization checks, leading to unauthorized access to sensitive data.
  • Broken Authentication: Weak or inadequate authentication mechanisms can provide an entry point for attackers to compromise user accounts, access sensitive data, or perform unauthorized actions. This vulnerability involves weak password policies, easily discovered or guessed credentials, session hijacking, or insufficient multi-factor authentication.
  • Excessive Data Exposure: APIs that expose excessive or unnecessary information can inadvertently disclose sensitive data. Attackers can exploit this vulnerability by accessing more data than required or gaining insights into the system's structure, potentially aiding further attacks.
  • Lack of Resources & Rate Limiting: Without proper rate limiting or resource allocation, APIs become susceptible to various attacks, including brute force, denial-of-service (DoS), and automated bot attacks. Attackers can overwhelm the system, leading to service disruption or unauthorized access.
  • Broken Function-Level Authorization: Similar to broken object-level authorization, this vulnerability arises when APIs fail to enforce access controls at the function or feature level. Attackers can exploit this weakness to gain unauthorized access to specific API functionalities or perform actions they shouldn't be allowed to.
  • Mass Assignment: Mass assignment vulnerabilities occur when an API includes additional parameters during object creation or modification. Attackers can exploit this by manipulating the API parameters to modify sensitive data or gain unauthorized access to functionalities.
  • Security Misconfiguration: Improperly configured security settings, default passwords, exposed debug information, or outdated software versions can create security gaps that attackers can exploit. API security misconfigurations allow unauthorized access, data leakage, or other malicious activities.
  • Injection Attacks: Injection attacks occur when untrusted data is executed as part of a command or query within an API. Common types include SQL injection, OS command injection, or NoSQL injection. Attackers can manipulate the input to execute arbitrary code, gain unauthorized access, or retrieve sensitive data.
  • Improper Assets Management: Failure to properly track, manage, or protect API-related assets, such as endpoints, credentials, keys, or tokens, can lead to unauthorized access or misuse. Attackers may obtain and abuse these assets to impersonate valid users, tamper with data, or gain elevated privileges.
  • Insufficient Logging & Monitoring: Inadequate logging and monitoring practices can hinder the detection of potential attacks or security incidents. Organizations can identify and respond to unauthorized access attempts or other malicious activities with comprehensive logs and monitoring systems.

Each of these attack vectors from the OWASP Top 10 illustrates a specific vulnerability that, when exploited, can compromise API security. However, it's crucial to recognize that these attack vectors rarely exist in isolation. 

Like the plane crashes and other catastrophes described in Gladwell's book 'Outliers,' API breaches often result from interconnected failures, where a sequence of vulnerabilities align to create a significant breach. This interplay emphasizes the importance of a comprehensive and layered security approach.

Where Traditional Network Security Fails

Most approaches to API security are based on network traffic analysis or WAFs. Yet, both methods fail to stop the most common API attack vectors because the attacks look like normal traffic. Effective API security requires both a greater level of data visibility and also the ability to analyze calls individually and in real-time, not only in the aggregate. 

A Comprehensive Approach to API Security

In order to effectively protect your APIs and to avoid the corresponding sequences of failure that lead to significant breaches, it's essential to do more than just traditional network security. You need to bridge the gap between security and application teams and address the unique security challenges presented by APIs

A robust approach to protecting APIs should cover all of the basics, but it should also incorporate the following:

1) In-Line, Real-Time Inspection of API Calls at the Application Layer

You can actively monitor and analyze the traffic flowing through their APIs by implementing in-line, real-time inspection of API calls at the application layer. This lets you identify suspicious activities, anomalies, or unauthorized access attempts in real-time. An inspection like this enables immediate response and mitigation, minimizing the window of opportunity for attackers to exploit vulnerabilities.

2) Preventative Controls To Block Malicious API Calls

Preventative controls are essential for proactively blocking malicious API calls. This includes implementing measures such as input validation, sanitization, and strict adherence to API security standards. By validating and sanitizing incoming API requests, you can mitigate the risk of injection attacks or other forms of data manipulation. Implementing strict controls at APIs' entry points helps you ensure that only legitimate and authorized requests are processed.

3) Centralized audit with application-layer visibility

Maintaining a centralized audit trail with application-layer visibility is crucial for comprehensive API security. This lets you track and monitor API activities, including authentication attempts, data access, and modifications. By aggregating and analyzing these logs centrally, you can detect unauthorized activities, identify potential security gaps, and respond promptly to security incidents. This visibility provides valuable insights into the overall security posture and helps in compliance with regulatory requirements.

4) Detection & Response (D&R) Built on Both Application and Network Logs

API security requires a holistic approach to detection and response. By leveraging application and network logs, organizations gain a more comprehensive view of potential threats and attacks. Application logs provide insights into API-specific activities, while network logs offer a broader context of network-level activities. Combining these logs lets you correlate events, detect advanced attack patterns, and respond effectively to potential breaches. This integrated approach ensures that no potential security incidents go unnoticed and appropriate countermeasures can be implemented swiftly.


A comprehensive and layered security approach in API security addresses vulnerabilities at multiple levels, mitigating risks and reducing the likelihood of successful attacks. It combines real-time monitoring, preventative controls, centralized audit trails, and robust detection and response mechanisms. Implementing such an approach bolsters your API security posture, safeguards sensitive data, maintains compliance, and protects your organization's reputation. 

Remember, the security of APIs is only as strong as the weakest link, and a layered approach helps you ensure that multiple layers of defense are in place to thwart even the most sophisticated attacks, eliminating the possibility that multiple failures can align and lead to an API data breach catastrophe.


Published on Jun 20, 2023
Jeremy Snyder
Written by Jeremy Snyder
Jeremy is the founder and CEO of FireTail, an API security platform with a mission to secure the world's APIs. An industry veteran, Jeremy worked as an IT and cybersecurity practitioner for 10 years before transitioning into cloud and cybersecurity for new markets with companies such as AWS, Cambridge Intelligence, and DivvyCloud.


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