API security API gateways least privilege access

API Security Principles That Are Here to Stay

Application programming interfaces (APIs) have grown more popular in recent years, as businesses attempt to make their apps smoother and easier to use both behind the scenes and in customer-facing interactions. While APIs are convenient and increasingly relied upon, they offer unique difficulties when it comes to cybersecurity. Each API is different, so security practices that work for one may not work for another, and most API attacks exploit gaps in business logic, rather than measurable vulnerabilities that would turn up in standard testing.

Fortunately, although there are no one-size-fits-all solutions, there are best practices and guiding principles that can shape your approach to API security. These principles are foundational to creating and employing APIs that protect user data and are not overly vulnerable to cyberattacks.

API Gateways

An API gateway is an added layer of communication between programs that handle API requests. The gateway is a centralized passage that can manage multiple APIs and multiple apps, not only overseeing the requests but detecting abnormal or suspicious behavior. With features such as authentication and rate limiting, the gateway assists developers in understanding tactics used by bad actors in attempted API attacks. It makes it easier to test different versions of an API, monitor performance, and identify abuse or overuse, and it consolidates metrics from several programs and interfaces in one place.

Least Privilege Access

The principle of least privilege is a cybersecurity staple for good reason. In essence, it simply means that each user only has access to the data, networks, systems, and devices that are absolutely necessary for their usage. This ensures that users have limited information and less power to either use that information for nefarious purposes or inadvertently allow it to fall into the hands of someone else who will do so.

Least privilege access can help to mitigate one of the predominant security risks of APIs: they often send more information than is requested or required for the operation being performed, leaving it up to the application to sift through the excessive data for what the user actually needs. An API system that limits which users can make what types of requests make this issue less of a vulnerability and limits the exposure of data.


One of the main concerns in API security is the fact that the landscape is always shifting, and “documentation is always incomplete and often out of date.” Without accurate and up-to-date documentation, it can be all but impossible to understand an API, how it works, where its vulnerabilities are, and how to effectively secure it. In addition to documenting each API, it is also recommended to maintain an API inventory to ensure that security teams have an accurate view of the attack surface.

Proper documentation is integral to performing design reviews, conducting security testing, and protecting an API from potential threats. Documentation must be kept updated with any changes that are made during development, testing, and production. It shows how the API is built and how it is integrated with client and server programs, which increases visibility for all involved. Using machine formats for API documentation, like OpenAPI Specification (OAS), makes basic testing and protection easier to navigate. Weak documentation can allow vulnerabilities to slip under the radar and leave your API unknowingly open to attacks.

Security Testing

As with any software, it is necessary to conduct security testing during both development and production. Testing tools that rely on scanning, including Static Application Security Testing (SAST) and Dynamic Application Security Testing (DAST), are not equipped to detect all of the problems that APIs are particularly susceptible to, but they can identify configuration issues and vulnerabilities in the software. Recent trends, like the combination of SAST and DAST into Interactive Application Security Testing (IAST) and the expansion of DAST to be considered for risk assessment as well as detecting vulnerabilities, have increased the usefulness of this kind of testing for API security.

When it comes to APIs, testing goes hand in hand with monitoring and logging. In order to effectively test an API for exploitable flaws, it is crucial to understand the baseline of behavior for that particular API and employ technologies and strategies that focus on identifying when there is suspicious activity. Traditional security measures do not have the ability to track traffic to the extent necessary to detect abnormal behaviors or gaps in security.


It can be daunting to try to take on the challenge of API security due to how different it is from standard application security. APIs are always changing, the attack methods are often unique, and traditional security measures are unable to detect or address some of the key issues concerning APIs specifically. Although it can be daunting to take on the task of protecting your APIs from cyberattacks, especially given that each API is unique, the above principles are important to consider for everyone and should help you figure out where to start.

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