An API, or application programming interface, defines the protocols for communication among software components. API security is the protection of network-exposed APIs that are both produced and consumed by your enterprise. This entails the use of common security controls relevant to APIs such as rate-limiting and the authentication and authorizations of services, requests, and users. Additionally, it means understanding things like data provenance and where to seek context during design or review discussion. Going beyond just buying new tools, robust API security is an offshoot of a security-centric culture.  

Here are the following best practices to ensure API security for your enterprise:

1. Apply rate-limiting

Within the context of computer networks, rate-limiting titrates the rate of requests that are sent or received by a network interface controller. Rate-limiting can be employed as a way to prevent denial-of-service (DoS) attacks and limit web scraping. Determining a maximum threshold above which subsequent requests will be rejected (for example, 5,000 requests per day for every account) can prevent DoS  attacks.

2. Decrease unnecessary data exposure

It is possible for APIs to reveal more information than is necessary, whether it be in the volume of unnecessary data that returned to the API or information that discloses too much about the API endpoint. This commonly happens when, instead of filtering data to the endpoint, an API leaves the task of filtering data to the user interface. It is crucial that APIs only return as much information as is necessary for them to carry out their function. Additionally, enforcing data access controls at the API level, monitoring data, and obscuring if the response contains sensitive data.

3. Employ a strong authentication and authorization solution

The lack of robust authentication and authorization protocols are among the major concerns of APIs that are publicly available. Broken authentication happens when the enforcement of authentication does not happen with APIs (this is often the case with private APIs) or when an authentication factor (something the client knows, has, or is) can be easily breached. it is critical for organizations to strictly control access to APIs as they provide an entry point to an organization’s database.

4. Encrypt traffic using TLS

Transport Layer Security (TLS) is the successor of the now-deprecated Secure Sockets Layer (SSL). It is a cryptographic protocol designed to provide communications security over a computer network and is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible. The TLS protocol is meant to provide data privacy and integrity across communicating computer applications.

It is common for some organizations to choose not to encrypt the API payload data considered to be non-sensitive. However, for organizations whose APIs regularly exchange sensitive data such as user credentials or credit cards and other financial information, TLS encryption should be considered obligatory and indispensable.

5. Inventory and manage your APIs

Securing and managing your entire suite of APIs, whether in the dozens or hundreds of publicly available ones, requires awareness of them – hence the need for taking stock or inventorying them. To discover and inventory your APIs, conduct perimeter scans and work with your Development Operations (DevOps) team to manage them.

6. Make security a priority

It is a no-no to regard something as crucial as API security as just an afterthought or “someone else’s problem.” You must recognize that your business stands to lose a lot with unsecured APIs, so you must make security a priority and build it into your APIs as they are being developed.

7. Remove extraneous information that’s not meant to be shared

APIs are developer’s tools that often contain passwords, keys, and other information that must be removed before they are made publicly visible. However basic this is, it is a step that is often overlooked. Your enterprise should incorporate scanning tools into DevSecOps processes to mitigate the accidental exposure of sensitive information.

8. Utilize the Principle of Least Privilege (POLP)

The Principle of Least Privilege (POLP) is a security principle that limits the access rights of users to only what is strictly required, that is the bare minimum, required to execute their jobs. POLP is also otherwise known as the principle of minimal privilege or the control principle. Additionally, POLP can also restrict access rights for applications, systems and processes to only those who are authorized. This principle should be applied equally to APIs.

9. Use web application firewalls

A web application firewall (WAF) protects your web applications from application-layer attacks that include, but are not limited to, cross-site scripting (XSS) SQL injection, or cookie poisoning. App-related attacks provide an easy gateway to sensitive data.  It is crucial for WAFs to understand API payloads, or the actual data pack that is transmitted.

10. Validate inputs

API validation means figuring out if the data transmitted to the API is any good or not. Validation can take place on the server-side or the client-side. Traditionally, both client and server-side validation play a role, encompassing different use cases. Your enterprise should never transmit input from an API through to the endpoint without validating it first.

Conclusion

Applications and systems now rely on a complex network of APIs exposed through a variety of public and private networks. Your enterprise needs to make the effort to understand how these changes affect the various elements of your security systems and make sure that security is incorporated into software that consumes and exposes APIs at the right place at the right time.