3 API Vulnerabilities to Look Out For

Application programming interfaces (APIs) have become an integral part of the software development life cycle. The advent of the cloud, microservices, SaaS, and containers have all increased software development complexity. The need for APIs has been around for some time now.

What's Great About APIs?

What makes APIs so special? The answer is simplicity.

APIs provide a clean abstraction for building and consuming services. This abstraction layer allows developers to focus on business logic without worrying about the plumbing details.

What's Problematic About APIs?

Since this abstraction layer is a relatively new concept, developers have had to learn many new things while building APIs. And that means developers learned a lot of lessons the hard way.

Every week, new vulnerabilities come to light that let attackers exploit your API. This is why API security is essential, especially for companies that depend on APIs for business.

In this blog post, we'll look at some of the most common and dangerous API vulnerabilities. We'll explore how a malicious entity can exploit them to damage your API and how you can mitigate them.

Understanding APIs in Depth

Put simply, APIs are a way for two digital devices to talk with each other. The devices could be software applications, websites, or mobile applications. APIs are crucial to operating all kinds of modern websites and applications, including e-commerce stores and mobile apps.  

Put another way, APIs are a method for different software programs to interact. Usually, a client program makes requests for information to an API by sending HTTP requests to a server program implementing the API. Then, the server program returns data to the client.

APIs are essentially the little bits of code that allow one program or service to talk to another. They act as translators in their most basic form, making it possible for an app to understand and interact with a service.

For example, let's say you want to use the Google Maps API to add a map to your website. That API will give you a set of rules and guidelines on how to do that. Also, it'll provide you with the code you need for your website.

What Is API Security?

API security protects the integrity of APIs—both the ones you own and the ones you use. This type of security is essential because it can provide you with an advantage over competitors who may not have the same level of API security. It's a lot like physical security, but with APIs.

API security is the act of keeping your API safe from outside attacks. You protect consumers and assets, and you reduce the amount of time your API spends under attack.

Any company that has a website is at risk for attacks on the site. Similarly, if a company has a mobile app, that app is at risk for attacks. And if a company has an API, then that is at risk for attacks. The best way to protect against API attacks is to invest in API security.

Why Is API Security Important?

Security is a crucial factor for any business. As a business owner, you have to ensure your website is secured from all possible attacks. But what about APIs? They're a critical part of the modern app economy, yet they're also the most vulnerable and easiest to attack.  

With an unprotected API, anyone can gain access to your data. And that's precisely what happened to the largest employment social media site in the world (LinkedIn) and an American microblogging and social networking platform (Parler).

The most fundamental problem with API security is a lack of understanding of the risks involved. This lack of knowledge makes it easy for companies to dismiss the importance of API security.  

Why is there a lack of understanding? Well, people think about the security of their APIs only when there's a problem. This is evident because most companies don't have a centralized, continuous, and automated solution that handles the security of their APIs.

Unfortunately, this approach is dangerous. It exposes APIs to several risks, including, but not limited to, cyberattacks and data leaks.

3 Common API Vulnerabilities

APIs are an attack vector that hackers can use to access a business's data. This is why it's vital to treat APIs with the same level of importance as web applications and web services.

Let's look at the most common API vulnerabilities found today.

API Vulnerability 1: Authorization/Authentication Flaws

Authorization/authentication flaws are the most common vulnerability in API. Why? Two reasons: First, they're the most accessible vulnerability to exploit. Second, they're the most likely vulnerability to go undetected.  

When the attacker knows the format of the request and all the parameters required, it's straightforward for that person to craft a request that the server will accept.

Let's look at an example to better understand this.

There's an API that uses a JWT token for authentication. The point of the API is to fetch user details from the database once the user signs it. While developing the application, the developer missed adding a check as to whether the JWT token is present or not. And this can lead to unauthorized access to the API if a hacker removes the JWT token from the request.

How Can You Avoid Authorization/Authentication Flaws?

Let's look at a few ways to do this.

• Always protect your API using authentication (cookies or JWT).
• Expire the JWT token or cookies after a specific time.
• Always use middleware to validate whether the request is authenticated.
• Never use a guessable user ID or any insecure ID.
• Use strong secrets for generating cookies or JWT tokens.

API Vulnerability 2: Lack of Resources and Rate Limiting

When you're developing APIs, understanding how they access and distribute data is essential. Rate limiting is one of the critical ways you (as an API service provider) can retain control over the data output.  

While APIs may not impose restrictions on the size or number of resources the client requests, you can set your own restrictions on how many requests can be made within a given period. These restrictions are rate limits.

Rate limiting is a form of throttling, which is a process that ensures fair, equitable, or safe use of a resource (such as a server) by imposing a limit on the amount others can use it. All API services should have rate limiting to prevent any client or user from consuming too much of their resources.

How Can You Avoid Rate-Limiting Flaws?

Here are three of the most important ways.

• Consistently implement rate limiting for all APIs (internal or public).
• Use the API gateway to filter out spam API requests.
• Minimize the number of API calls (this is called throttling or debouncing).

API Vulnerability 3: Injection Attacks

An injection attack happens when an attacker manipulates data to exploit a weakness in an application. A successful injection attack can cause a system to crash or expose sensitive information and compromise the entire system.

Some common types of injection attacks are:

• SQL injection
• NoSQL injection
• Command injection
• LDAP injection
• XML injection

The most common injection attack is SQL injection. In this attack, the attacker sends an SQL query as the user input. The web application processes the query and returns the results to the attacker.

For example, let's say an input field allows the user to enter his or her username. The attacker enters the following query:  

SELECT * FROM Users WHERE Username='root'

As a result, the application returns all the information about the user with username root.  

How Can You Avoid Injection Attacks?

Follow these rules to prevent these types of attacks.

• Never trust user input.
• Use parameterized queries and stored procedures.
• Never pass user input directly to the back-end server.
• Use escaping to escape special characters.
• Always use a strong firewall.

Where to Learn More

We hope you enjoyed this post about API vulnerabilities. Here at Traceable AI, we know how important it is to keep your API safe so it doesn't become a security threat. We know that there are many ways to protect your API from vulnerabilities. You can find more information on our blog. Also, we encourage you to check out our detailed guide, which offers a more in-depth view of how to avoid these common API vulnerabilities.

This post was written by Keshav Malik. Keshav is a full-time developer who loves to build and break stuff. He is constantly on the lookout for new and interesting technologies and enjoys working with a diverse set of technologies in his spare time. He loves music and plays badminton whenever the opportunity presents itself.