APIs play an essential role in the modern enterprise, and their value will continue to grow as new applications, and IoT devices are created. APIs make integrations and connecting ecosystems much easier for developers, which has added benefits for enterprises and their customers. But with a growing number of smaller application “pieces” trying to communicate with each other, APIs (your own and those from third parties) are becoming increasingly challenging to secure.

For that reason, organizations should, use a layered security approach that includes security controls such as authentication, authorization, encryption, denial-of-service protection, and ongoing monitoring. This layered approach combines several methods to protect your APIs. While each individual approach within this multi-layered approach covers a specific focus area, the unified effect increases the chances of stopping API breaches. But before presenting some API security best practices, let us introduce the main API security issues that can put your business assets at a risk. Negligence with API security can cause massive repercussions, especially if the application’s user base is too high.

Top security issues in APIs:

  • Broken Object Level Authorization

APIs tend to expose endpoints that handle object identifiers, creating a wide attack surface Level Access Control issue. Object level authorization checks should be considered in every function that accesses a data source using an input from the user.

  • Broken User Authentication

Attackers often compromise authentication tokens or implementation flaws to assume other user’s identities temporarily or permanently due to incorrect implementation of authentication mechanisms. Compromising a system’s ability to identify the client/user, compromises API security overall.

  • Excessive Data Exposure

Looking forward to generic implementations, developers tend to expose all object properties without considering their individual sensitivity, relying on clients to perform the data filtering before displaying it to the user.

  • Lack of Resources & Rate Limiting

In most cases, APIs do not impose any restrictions on the size or number of resources that can be requested by the client/user. This can impact the API server performance, leading to Denial of Service (DoS), and also leave the door open to authentication flaws such as brute force.

  • Insufficient Logging & Monitoring

Insufficient logging and monitoring, coupled with missing or ineffective integration with incident response, allows attackers to further attack systems, maintain persistence, pivot to more systems to tamper with, extract, or destroy data.

As said above, the most critical API risks are data overexposure, lack of resources, no security configuration, insecure user-level authorization, and broken objects. Clearly, it is essential to ensure the security of the API so that application user data remains safe and the application is secure and trustworthy.

Here are eight best practices to ensure APIs are shielded and do not lead to critical security exposures.

1. Identify vulnerabilities

The only way to effectively secure APIs is to know which parts of the API lifecycle are insecure. Of course, that’s easier said than done, especially as the organization’s use of APIs scales. It is important to consider the whole API lifecycle, since APIs need to be considered software artifacts on their own and, as such, must follow a complete lifecycle, including maintenance and retirement.

2. Use strong Authentication and Authorization

Many publicly available APIs have a major issue of zero or insignificant authentication and authorization. Many APIs are the entrance to the database of the organization, so it is essential to strictly control the authentication and authorization so that the database is not exposed. Poor or non-existent authentication and authorization are major issues with many publicly available APIs. For authentication, developers can use a powerful token-based tool known as OAuth. It is a framework that authorizes the information to be shared with a third party without disclosing the user credentials.

3. Identify vulnerabilities in the API

To make an API effective against security threats, it is essential to know which parts of the API cycle are insecure and vulnerable to security risks. It might be pretty challenging to comprehend this, as a software organization might use thousands of APIs at a time. The best way to identify a vulnerability is by rigorous testing. The vulnerabilities must be identified in the initial development phase so that rectifying them becomes comparatively easy and quick.

4. Don’t expose more data than necessary

Some APIs reveal far too much information, whether it’s the volume of extraneous data that’s returned through the API or information that reveals too much about the API endpoint. This typically occurs when an API leaves the task of filtering data to the user interface instead of the endpoint. Ensure that APIs only return as much information as is necessary to fulfill their function. In addition, enforce data access controls at the API level, monitor data, and obfuscate if the response contains confidential data.

5. Encrypt data

This cannot be stated more strongly or more often: All data, especially personally identifiable data, should be encrypted using a method such as Transport Layer Security (TLS). Developers should also require signatures to ensure that only authorized users are decrypting and modifying data.

6. Use an API gateway

API gateways act as the major point of enforcement for API traffic. A good gateway will allow organizations to authenticate traffic, as well as to control and analyze how APIs are used.

7. Adopt a zero-trust philosophy

In the perimeter security model, what’s “inside” is trusted and what’s “outside” is not trusted. The network is not that simple anymore, which is why a zero-trust model makes sense, especially with remote users. With a ZTM, the security focus shifts from location to specific users, assets, and resources.

8. Use Tokens

Access tokens allow an application to access your API. Once the authentication and authorization process is completed, an access token is provided. Tokens enable you to create trusted identities and assign tokens to those identities to control access to the API.

As mentioned before, APIs have become an integral element in creating modern applications, especially for smartphones and modern IoT devices. Since using an API means pulling the information from the outside source to your application, it poses a significant security risk. Too often, APIs are developed with the functionalities in mind, not the security, that’s why organizations must take API protection more seriously and dedicate effort to ensure end-to-end security.