APIs are the backbone of modern software architecture, which allows easy integration between services, applications, and platforms. However, this interconnectivity poses various risks, like APIs are now one of the largest and fastest-growing attack surfaces in modern digital environments. According to industry data, over 83% of internet traffic today involves APIs, yet a large percentage of these endpoints are deployed without robust security controls, proper authentication, or continuous monitoring.

As organizations expand their infrastructure and adopt microservices, third-party integrations, and mobile applications, the complexity of API ecosystems grows with the risks. Attackers exploit weak API configurations, excessive data exposure, and broken access controls to gain unauthorized access, steal data, and interrupt operations. API breaches have resulted in a variety of financial losses and legal fines, making API security a top priority for security engineers.

This blog will cover the top ten API security risks, mitigation strategies, and tools and technologies for improving your API security posture.

What are API Security Risks?

API security risks are vulnerabilities that result from the design, build, and support of an API. Vulnerabilities can expose systems to risks related to unauthorized access, data privacy breach, privilege escalation, and denial of service. These attacks can reveal important information and allow attackers to exploit backend systems to steal user identities.

Common security threats include poor authentication, lax access limits, invalid inputs, and a lack of traffic monitoring. APIs provide direct access to an organization's data and services, so even minor misconfigurations can lead to exploitation. Addressing these threats needs a strategic approach that includes security-by-design principles, runtime defenses, and continuous testing.

Top 10 API Security Risks You Need to Know

API ecosystems expose multiple threat vectors that attackers exploit to gain unauthorized access, extract sensitive data, or disrupt services. The following are the ten API security threats that every organization needs to address.

1. Injection Attacks

Injection attacks occur when unvalidated input is sent through an API and executed by backend components. This includes SQL, NoSQL, and command injections. Attackers make malicious payloads in parameters or request bodies to manipulate internal systems. Successful injection may result in data theft, system compromise, or service disruption. These risks often originate from insecure input handling and a lack of parameterization. Input validation and strict data schemas help mitigate injection vulnerabilities.

2. Broken Authentication and Authorization

Source: Freepik

APIs without proper authentication expose endpoints to spoofing and unauthorized access. If authorization checks are absent or incorrect, users who don't have authorization can also access data and perform actions. Attackers use weaknesses such as token replay, hardcoded credentials, and improper identity flows. These flaws are harmful in APIs that serve sensitive data. Security engineers should apply multi-factor authentication, short-lived tokens, and role-based access controls to protect systems. Each endpoint must enforce both authentication and authorization.

3. Excessive Data Exposure

When APIs return more information than required, attackers extract sensitive data directly from responses. When back-end systems send entire objects and expect the client to filter the fields, fields like passwords, emails, or internal identifiers are unintentionally revealed. The attackers initially look at the response payloads to extract that data at scale. This data breach can cause a compliance risk, and it helps them with regard to lateral movement. Responses should only include the minimal approved fields that contain sensitive data. This data should be hidden or deleted.

4. Insufficient Logging and Monitoring

APIs without logs allow attackers to perform harmful actions without detection. A lack of insight into request patterns, errors, or unusual activity makes it harder to identify attacks. Without logs, security engineers cannot identify incidents or compromised endpoints. Poor monitoring also affects response to credential stuffing, probing, and abuse. Real-time notifications and log aggregation help detect and respond to threats early. Logging should have authentication attempts, access failures, and abnormal usage.

5. Lack of Rate Limiting

Rate limits prevent APIs from getting overloaded or abused, but many APIs do not have enough throttling. Without limits, attackers can use brute-force logins, steal data, and execute denial-of-service attacks. This leads to service outages, data leaks, and higher costs. APIs should set limits for each user, IP address, and endpoint. Quotas and burst controls can help stop automated misuse. Adding rate limits, authentication, and anomaly detection improves security overall.

6. Broken Object Level Authorization (BOLA)

Source: Medium

BOLA occurs when an API fails to validate user or access rights to specific objects. Attackers manipulate IDs or object references in requests to access resources that don't belong to them. This is common in REST APIs that use predictable object IDs. Without contextual authorization checks, APIs expose user data and internal records. Every object request must enforce ownership validation. Using contextual access checks per object helps to mitigate this risk.

7. Improper Asset Management

Shadow APIs, outdated versions, and untracked endpoints increase the attack surface. Many organizations do not have an accurate inventory of their APIs. As a result of the lack of security patches, outdated services remain vulnerable. Insecure documentation and test environments also expose internal information that attackers can scan to get neglected assets. Continuous discovery, classification, and lifecycle management are essential for maintaining visibility and reducing exposure.

8. Server-Side Request Forgery (SSRF)

SSRF vulnerabilities allow attackers to manipulate API requests to access internal or third-party systems. After exploiting SSRF, attackers make the server send unintended requests, often to internal services. This avoids perimeter defenses and reveals sensitive metadata, credentials, or cloud services. APIs that accept URLs, redirects, or file fetch requests are especially vulnerable. Strict allowlists, DNS resolution controls, and blocking metadata IPs help lessen the impact of SSRF.

9. Unsafe Consumption of APIs

When organizations trust third-party APIs without validation, they pose external risks. If upstream APIs are compromised or misconfigured, malicious data can enter trusted systems. Lack of schema enforcement and response validation may worsen the impact. APIs must treat responses from external services as untrusted. Defensive coding, response validation, and fail-safes are critical to mitigating supply chain risks via APIs.

10. DDoS Attacks

Source: Katz blog

APIs are frequently targeted by Distributed Denial-of-Service (DDoS) attacks due to their direct access to backend systems. Attackers overwhelm endpoints with requests, consuming server resources and bandwidth. This can lead to downtime, poorer performance, and financial loss. Unauthenticated endpoints are especially vulnerable to volumetric attacks. WAFs, global rate limits, and behavioral analysis all help fight DDoS attacks at the API layer.

How to Mitigate API Security Risks

Mitigating API security risks needs systematic controls across authentication, validation, monitoring, and integration. The following are the strategies every organization should implement to secure its APIs effectively.

Enforce Strong Authentication Protocols

Use robust authentication standards like OAuth 2.0 with access scopes, token expiration, and refresh tokens. Avoid using basic authentication or hardcoded credentials in production systems. Implement multi-factor authentication for administrative or sensitive activities, and validate tokens on all queries. Strong authentication can help to prevent illegal access.

Use Schema Validation

Validate each incoming API request against a tight schema that specifies the acceptable attributes, formats, and data types. Reject requests with unknown or malicious inputs. Enforce output schemas to prevent excessive data exposure. Validation prevents injection, type confusion, and logic flaws. Define and maintain JSON or XML schemas as part of your API design.

Apply Rate Limiting

Rate restriction limits the API requests sent during a given duration, reducing the harm of misuse. Set limits based on the user's identity, IP address, or API key to prevent abuse. Burst limits can be used to handle temporary spikes without causing system performance degradation. Quotas defend backend infrastructure against brute-force, scraping, and DDoS attacks. Logging rate-limited events helps in detecting unusual patterns and possible threats.

Log and Monitor All API Requests

Keep detailed logs of all API calls. Include metadata such as IP, method, endpoint, status code, and user ID. Monitor these logs continuously to spot unusual traffic, access violations, or a sudden rise in error rates. Use notifications to know about brute-force attacks or patterns of abuse. Store logs securely for compliance and forensic purposes. Logging helps with both detection and response.

Continuously Test APIs

Perform regular security testing during development and after deployment. Use tools for automated vulnerability scanning, fuzzing, and misconfiguration checks, and integrate testing into CI/CD pipelines for security. Retest APIs after upgrades, especially if the changes alter authentication or data flows. Continuous testing helps to identify regressions before they become exploits.

Manage API Versions

Monitor all API versions in use and remove outdated ones regularly. Make sure outdated APIs are taken out of production and are no longer publicly accessible. Use versioning in URI paths or headers to manage updates without interrupting existing clients. Document how each version behaves and what access controls it has. Version control lowers the attack surface and limits exposure to legacy systems.

Secure Backend Integrations

Treat all upstream and third-party APIs as untrusted sources. Check and clean all external data before it is processed by internal systems. Use network segmentation or service meshes to isolate and manage backend integrations. Monitor third-party traffic for any issues, like unusual behavior or changes in the schema, on an ongoing basis. Strictly follow the validation criteria to minimize dependency issues. Limiting external influence on core systems and preventing supply chain attacks are two benefits of securing integrations.

Top Tools and Technologies to Mitigate API Security Risks

Mitigating API security risks effectively requires various tools that handle both development-time and runtime threats. Here are the tools security engineers should use to secure APIs at scale:

Akto

Akto continuously monitors API traffic and tests for vulnerabilities like BOLA, injections, and broken authentication. It integrates into CI/CD pipelines for early security measures. With automated test generation and real-time alerts, it gives a full view of API risks. Additionally, Akto facilitates runtime protection by promptly detecting anomalous activity. In various settings, it assists security teams in enforcing secure coding practices.

OWASP ZAP

ZAP is a trusted tool for detecting vulnerabilities during active API scans. It identifies common issues such as injection flaws, broken access controls, and unencrypted endpoints. Its scripting engine lets security engineers replicate complex attacks. ZAP works with automation workflows for scheduled testing. Its free model makes it ideal for continuous security checks.

Burp Suite

Burp Suite is a toolkit for deep API testing, including intercepting requests and analyzing logic flaws. It supports automated scans and also allows manual exploration for custom workflows. The tool is great at finding business logic vulnerabilities and authorization issues. Security engineers use their extensions for specific security analysis. It is a standard tool in penetration testing environments.

Postman Security Testing

In addition to functional tests, Postman validates headers, tokens, response codes, and security assertions to allow security engineers to automate security tests in collection procedures. Assertions ensure that APIs can adhere to authentication requirements and the required data handling process. Postman helps to keep consistency around API security practices across teams. It also integrates well with CI/CD, helping facilitate continuous security tests regularly.

Final Thoughts

Securing APIs demands continuous risk checks and real-time protection. Attackers target APIs because they allow them to gain data and enter systems. A mature API security program integrates discovery, testing, monitoring, and enforcement into the development lifecycle.

Akto is an AI-powered API security platform built for security engineers to secure APIs across staging and production. Akto integrates easily with CI/CD pipelines, providing actionable insights that correspond with development practices. With Akto, API security becomes continuous, scalable, and integrated into your engineering workflow, without slowing down teams. Schedule a API security demo with Akto to eliminate API blind spots and proactively protect your organization from evolving API risks.