The OWASP API Top 10 Vulnerabilities & How DAST Can Save You from Disaster
APIs are the backbone of modern applications, powering everything from mobile apps to enterprise integrations. But with great power comes great responsibility—especially when it comes to security. The OWASP API Top 10 outlines the most critical API vulnerabilities that attackers exploit. Fortunately, DAST can help you identify and fix these issues before they become breaches. Let’s dive into the OWASP API Top 10 and see how DAST plays a crucial role in preventing API security disasters.
1. Broken Object Level Authorization (BOLA)
One of the most common and dangerous API vulnerabilities, BOLA occurs when an API allows users to access objects they shouldn’t be authorized to see. Attackers manipulate API requests by changing object IDs in order to access or modify data belonging to other users. This flaw arises when applications fail to properly enforce authorization at the object level, leading to potential data breaches and leaks of sensitive information.
DAST tools simulate real-world attacks to test for broken object-level authorization. By analyzing API request and response patterns, DAST identifies endpoints that expose unauthorized data. Through automated testing, organizations can detect and remediate BOLA vulnerabilities before attackers can exploit them, ensuring strict access control measures are enforced at every level.
2. Broken User Authentication
Authentication mechanisms ensure that only legitimate users can access an API, but weak implementations can allow attackers to bypass these controls. Issues like weak passwords, missing multi-factor authentication (MFA), exposed API keys, and improper session management can lead to account takeovers and unauthorized access. Attackers often exploit these weaknesses through credential stuffing, brute force attacks, and token hijacking.
DAST tools assess API authentication by simulating various attack techniques to detect vulnerabilities. They test for insecure login endpoints, improper session expiration, and missing security best practices like rate limiting on authentication requests. By identifying these weaknesses early, DAST helps organizations strengthen their authentication mechanisms and prevent unauthorized access.
3. Excessive Data Exposure
Many APIs return more data than necessary, making it easy for attackers to extract sensitive information. Instead of filtering responses based on user permissions, APIs often expose full database records, relying on front-end applications to hide unnecessary fields. This approach can lead to the accidental exposure of personally identifiable information (PII), financial records, or confidential business data.
DAST scans API responses to identify instances where excessive data is returned. By analyzing what information is included in responses, security teams can enforce data minimization principles, ensuring that only essential data is exposed. This reduces the attack surface and prevents attackers from exploiting leaked information.
4. Lack of Resources & Rate Limiting
APIs without proper rate limiting and resource controls are susceptible to denial-of-service (DoS) attacks, excessive data scraping, and abuse. Attackers can send a high volume of requests to overload the API, disrupting service availability. Without proper constraints, even authenticated users can abuse an API by making excessive calls to extract large amounts of data.
DAST tools test APIs for rate-limiting enforcement by simulating automated attacks that flood endpoints with requests. By identifying APIs that fail to implement proper resource limits, organizations can introduce protections like request throttling, user quotas, and adaptive security measures to mitigate abuse and ensure service reliability.
5. Broken Function Level Authorization
Function-level authorization controls determine which users can perform specific actions within an API. Weak enforcement of these controls can allow attackers to escalate privileges, gaining access to administrative functions or performing unauthorized operations. This vulnerability is particularly dangerous in multi-user environments, where users have different levels of access.
DAST tools evaluate API endpoints for improper role-based access control (RBAC) enforcement. By mimicking privilege escalation attempts, these tools help detect flaws in access control logic. Strengthening function-level authorization ensures that users can only perform actions aligned with their roles, preventing unauthorized activities and potential security breaches.
6. Mass Assignment
Mass assignment vulnerabilities occur when APIs allow users to update object properties without proper validation. Attackers can exploit this by modifying sensitive fields, such as user roles, account statuses, or pricing information, leading to unauthorized access or data manipulation. This happens when developers unintentionally expose internal object fields that should not be directly controlled by users.
DAST tools detect mass assignment risks by sending unexpected input variations to API endpoints. By analyzing how the API processes user-supplied data, security teams can identify improperly exposed fields and enforce stricter validation mechanisms. Implementing an allowlist approach, where only explicitly defined properties can be updated, helps mitigate this vulnerability.
7. Security Misconfiguration
Improper API configurations can expose sensitive data, enable debugging modes, or lack essential security headers. These misconfigurations often result from default settings, poor deployment practices, or incomplete security hardening. Attackers exploit these weaknesses to extract information about the API, identify attack vectors, or directly compromise systems.
DAST tools help identify security misconfigurations by scanning API responses for missing security headers, exposed error messages, and unprotected debug endpoints. By continuously testing API configurations, organizations can enforce best practices, remove unnecessary features, and ensure secure deployment settings.
8. Injection Attacks
Injection vulnerabilities occur when user-supplied data is improperly handled, allowing attackers to execute malicious code within an API. Common types include SQL injection, NoSQL injection, and command injection. These attacks can compromise databases, leak sensitive data, and even allow remote code execution.
DAST tools detect injection vulnerabilities by sending malicious payloads to API endpoints and analyzing responses for anomalies. By testing how APIs handle user input, DAST helps developers implement proper input validation, escaping mechanisms, and parameterized queries to prevent exploitation.
9. Improper Asset Management
APIs often have outdated, undocumented, or shadow endpoints that attackers can exploit. Poor asset management can lead to exposure of legacy APIs with unpatched vulnerabilities, increasing the attack surface. Developers may forget to deprecate old versions or leave test APIs exposed, unknowingly providing entry points for attackers.
DAST tools help organizations discover all accessible API endpoints, including forgotten or undocumented ones. By mapping API assets, security teams can identify outdated endpoints, enforce proper deprecation policies, and limit exposure to only necessary services, reducing the likelihood of exploitation.
10. Insufficient Logging & Monitoring
Without proper logging and monitoring, organizations lack visibility into API attacks and suspicious activities. This allows attackers to operate undetected, making it difficult to respond to breaches or track malicious behavior. A lack of proper alerting mechanisms further delays incident response, increasing potential damage.
While DAST does not log attacks directly, it helps identify gaps in API security that should be logged and monitored. Organizations can use insights from DAST tests to improve logging practices, set up real-time monitoring, and establish alerting mechanisms. Combining DAST with Security Information and Event Management (SIEM) solutions ensures rapid detection and response to API threats.
Why DAST is Essential for API Security
Unlike static testing methods, DAST interacts with your running API like an attacker would. It identifies real-world vulnerabilities in real time, ensuring that security flaws are caught before they reach production. By integrating DAST into your CI/CD pipeline, you can continuously test your APIs against OWASP API Top 10 threats and fix vulnerabilities before they become security nightmares.
Final Thoughts
APIs are high-value targets for attackers, and the OWASP API Top 10 highlights the most dangerous vulnerabilities lurking in your applications. With DAST, you gain an automated, attacker’s-eye view of your API security posture—helping you proactively fix issues before they become breaches. Don’t wait for a security disaster—secure your APIs with DAST today!
