An Essential Guide for API Security in your SaaS Products

API Security


Application Programming Interface, also known as API, is currently dominating the development market. Many modern enterprises, banks, autonomous vehicles, and IoT, have APIs tightly integrated into their infrastructure. This is because APIs allow developers to integrate external services without having to develop them from scratch.

API Security

Despite a number of obvious advantages, APIs also pose security threats like exposing application logic and other sensitive information like Personally Identifiable Information. APIs simply cannot be eliminated from development environments, so the only way forward is to secure APIs.

APIs Security

The API security framework consists of guidelines and solutions aimed at addressing the unique challenges of API security. The wide adaptation of API in the development environment also provides a large attack surface for cybercriminals. APIs have been around for years, but the approaches to adapting them have changed as a result of technologies such as mobile applications, cloud, and containers. According to the stats of Programmable Web, there are nearly 15,000 APIs in use for mobile and web applications alone. Such a large-scale adaptation also requires a modern security approach to counter ever-growing cyber-attacks.

Security Challenges for APIs

There are several security challenges that developers face during the development of a robust and modular application. Due to a spike in API-based cyberattacks, a software security organization named “The Open Web Application Security Project (OWASP)” has developed a top-10 list of security vulnerabilities common to web applications entitled “The OWASP Top 10”. Enterprises can plan their security framework based on these threats.

Security Challenges for APIs

Broken Object Level Authorization

APIs by nature can expose endpoints while handling object identifiers. Any function that accepts user input to access a data source can result in Level Access Control. These functions must be verified for object-level authentication.

Broken User Authentication

Another issue that can lead to unauthorized access is incorrect authorization implementation. An attacker can exploit the authentication tokens or pretend to be a legitimate user to gain access to the system.

Excessive Data Exposure

Often, developers include unnecessary sensitive data and leave filtering to the client, which can lead to serious security threats.

Lack of Resources and Rate Limiting

Unless resource-intensive requests from the client are restricted, they can degrade performance and lead to DDoS attacks.

Broken Function-Level Authorization

The absence or ambiguity of policies regarding the difference between the normal and administrative levels can lead to authorization vulnerabilities.

Mass Assignment

The mass assignment vulnerability occurs when developers assign data from the client-side without properly filtering it.

Security Misconfiguration

Another reason where APIs can pose security risks is security misconfiguration. Among the scenarios of security misconfigurations are misconfigured HTTP headers or inappropriate HTTP methods, open cloud storage, inadequate default configurations, to mention a few.


An injection attack is conducted by sending data in the form of queries or commands to interpreters through an untrusted source. As a result, an interpreter can be tricked to reveal some sensitive data. SQL Injection is a common Injection technique.

Improper Asset Management

APIs are likely to expose endpoints, unlike legacy web apps. Therefore, it is vital to keep track of API version details and configure hosts in the proper manner.

Insufficient Logging and Monitoring

Generally, persistent threats in a system are detected in at least 200 days and need to be handled by external security professionals. External assistance heavily relies on log files. The lack of enough log files can not only impede threat investigation but also give the attacker an opportunity to penetrate the system undetected.

Best Practices to Secure APIs

Although the APIs do have some security issues, you shouldn’t let that deter you from taking advantage of this flexible and modular technology. Following security guidelines and implementing essential security controls can help you make the most of APIs. Here are some essential API security controls to follow:

API Security

Focus on Authentication and Authorization

The most basic way to improve system security is by validating users who intend to access the system. APIs do not operate independently rather they are integrated into the system. It is recommended to use multi-factor authentication instead of traditional username and password authentication.

Check Data on the Back End

Usually, enterprises invest a lot of their resources on the front end and ignore the importance of having a secure back end. In a properly secured back end, data is checked to prevent leakage as it leaves the system.

Third-Party API Security Tools

There are several API security tools and more continue to be introduced to the market. These tools can help with code verification and deficiencies by using prebuilt security scans.

Time and Budget Allocation for Security Testing

Companies always feel excited to introduce new features to their products and services. Thus, companies do not pay attention to security testing and do not allocate enough time and resources to identify vulnerabilities in new releases.

Test for Command Injection

Input various operating system commands into API to check if the API is immune to injection attacks. The input commands must correspond to the operating system commands on the hosting server of API.

Test for Unhandled HTTP Methods

API-integrated web applications communicate with servers through HTTP methods like POST, GET, PUT, and DELETE. This simple task can create a system vulnerability if the server does not support HTTP requests. Although this is not the case most of the time, it can be verified by making a HEAD request to the API endpoint that requires authentication.

API Testing Tools

An enterprise that uses a DevOps philosophy and frequently releases patches for its products needs a testing tool to automate APIs security. The following are some open-source API testing tools to suit most enterprise requirements:

    • Postman
    • Swagger
    • JMeter
    • SoapUI
    • Karate
    • Fiddler

Bottom Line

Knowing the benefit of APIs, it is very hard to ignore them and not integrate them into your development environment. Sure, there are several security threats, but they can be addressed if you follow a few guidelines. As long as an organization implements continuous security controls and testing mechanisms along with the production of their products, they can introduce robust and safe digital products to the market.