8 API Security Best Practices You Should Know

An application that integrates seamlessly with other apps is profitable to a business. It makes life easy for customers and third-party developers can conveniently enhance the usability of the app too.

Unfortunately, this ease of connection with other apps can also attract malicious users. And as more businesses rely on APIs today, related web API security concerns are on the rise. Some API security companies reported a surge in harmful calls to their clients’ APIs of up to 681% between 2020 and 2021. In another report, IT experts interviewed by 451 Research said that over 41% of their companies suffered an API security incident in 2021.

Can web applications exploit the benefits of API while keeping a safe environment for users? That’s where API security comes in.

What is an API?

Application programming interface, abbreviated as API, is the term for a collection of functions that enable a developer to interact with an existing third-party web or mobile application. Through an API, a developer can write code for a program that functions in an existing web application or platform that they don’t own. By including an API, a platform is opening an entry point for other developers to access their system. Also, APIs enable data transmission between the host app and external users.

What is API security and why is it important?

Since an API is a gateway to online applications, cyber attackers target them to steal data within your platform or its servers. That’s why you’ll frequently come across API in cyber security topics. API security refers to the measures undertaken to safeguard or mitigate malicious attacks on APIs.

APIs are the server-side frameworks of mobile and web applications that store and relay data. If compromised, they not only expose your data but that of your users too. This can lead to huge losses.

Besides, a data breach damages your brand’s reputation and can lead to costly lawsuits, and no business or individual would want to use your API after a data breach as it could harm their apps, too. This makes API security an important consideration when designing an interface for your application.

API security best practices

When coding an API, understand the security risk and implement the API security best practices below to secure its architecture. This way, you’ll keep your business data and that of the API’s users safe.

1. Encrypt your data

A common API threat is the man-in-the-middle attack, where malicious users eavesdrop on the communication between an end-user and API. If successful, those eavesdropping will steal important information while in transit. The data may include user credentials, identification numbers and financial details.

An effective way of preventing such an attack is by transferring data in a scrambled or hidden form. Engage your partners and make an agreement to use secure transmission channels that use data encryption. Most REST APIs use HTTP, a network transmission protocol that’s easy to secure using transport layer security (TSL/SSL).

One way to ensure you encrypt your data is by validating your website domain. Simply obtain low cost and fast issuance certificate like domain validation SSL certification. Your users will enjoy 256-bit data encryption on your website whether browsing on mobiles or desktops. This will also encrypt any communication flowing through your API channels. 

It’s also necessary to encrypt information stored in your API. To cover data stored in your API, you may add a web application firewall.

2. Authenticate, authorize and validate requests

Consider a multi-pronged approach to monitoring access to your API infrastructure. Have in mind that hackers find it easy to access API channels by hijacking the identity of a legitimate user, so don’t trust every request made to your API. Instead, design your software to first verify the user’s identity before sending a response.

Authentication techniques to assess a request may involve using a password, a token, and multi-factor authentication. Multi-factor verification is helpful as it strengthens your verification process, making it challenging to intrude. Even if hackers guess passwords, it’s hard to make correct guesses when more than one level of authentication is required.

Once your API verifies the user’s identity, it should activate further controls to ensure a user access only the resources relevant to them. This controls what a user can or cannot do in your API environment. It’s helpful when the API can verify and authorize each request individually, even if they originate from a single user.

The third step is validating tokens before granting access. Bear in mind that tokens can fall into the hands of malicious users. Ensure safety by checking whether the token matches the code stored in your database.

Gaps in validation and authentication will pose various threats, including code injection, distributed denial-of-service (DDoS) attacks and data breaches.

3. API requests throttling and establishing quotas

A common trick with attackers is sending numerous requests to a system fast and consistently. Such requests may overwhelm your servers and create a window for cyber attackers to strike. That’s how brute-force attacks such as DDoS occur. Safeguard your API against this attack by limiting the number of requests your API server can process at a time. To achieve this, developers impose quotas and throttle a user’s connection to the API. It ensures a user can only make reasonable requests at a time, thus safeguarding against suspicious requests and excess API traffic.

4. Keep API activity logs

Always keep track of the requests your API is processing. In case you receive an error, make sure you troubleshoot immediately. Audit the error details and log them into the server. Keep a history that you can refer to when debugging future issues. By inspecting API log audits regularly, it will be easy to point out any suspicious activities.

5. Share minimal information

For every request, limit the responses to only what’s relevant. Take precautions, especially when responding to an error message. Have predefined email messages and encoded subjects that won't be easy to modify by third parties. Encrypt sensitive information and control who has access to what.

Avoid displaying IP addresses as they can easily show your location. You could employ resources such as an IP whitelist and blacklist to prevent unauthorized access to your API.

Being scarce with the information you share on an API will go a long way in safeguarding your data.

6. API Firewalls

API firewalls act as the gatekeepers of your application architecture. Every call entering and leaving your API must pass the security checks imposed through the firewall. Consider API security structured in the following layers:

• A demilitarized zone (DMZ): This is the basic layer that uses a firewall to perform basic functions such as monitoring message sizes and requests to prevent SQL injections and block intruders. Requests that pass this check can proceed to the second layer.

• Local Area Network (LAN): Here, advanced checks occur to verify the content of any data coming to the API.

The idea is to make your API security very tight so that hackers don’t have a field day breaking through and laying their hands on your API data.

7. Infrastructure

Make sure you deploy your API on strong network infrastructure. Hackers can still exploit a weak security network, outdated software and faulty hardware to steal data shared or stored on your API. To safeguard against this, make sure you use modern networking equipment and update software regularly.

Keeping up with software updates is crucial since most of these updates are designed to fix the latest security concerns. Modern equipment comes with improved security features that make it hard for hackers to access. They also work efficiently to minimize downtime; an opportunity cyber attackers utilize to execute their malicious attacks. 

8. Security tests

Get a clear idea of how your security measures will perform in case of an attack by testing them. It’s important to perform an initial test before deploying an API to determine whether the security features work as desired. Then, come up with a plan for continuous testing.

Ideally, you develop various scenarios that mimic real-life threats and introduce them into a perfectly working API. These should involve DDoS, stolen passwords, code injection and MITM, among other common threats. To ensure rigorous testing, stay abreast with the changing trends in API security threats.

Conducting regular security checks helps you to keep tabs on the health of your API. You’ll assess its ability to withstand rigorous attacks and make amends where necessary.

Final thoughts

Many popular software applications include an application programming interface (API). APIs make it easy for other developers to communicate with your app. Customers enjoy great services thanks to seamless integration with an app. The more users can easily connect to your app, the more profitable your business becomes.

The level of security you implement for an API depends on what it does. An image-sharing API might require a lower level of security than APIs designed to facilitate financial transactions. Use the ideas above to find a suitable method of protection for your API. It’s possible to implement several measures, depending on what your API security demands.