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API Security

What is API Security?

Application programming interface (API) security refers to the practice of preventing or mitigating attacks on APIs. APIs work as the backend framework for mobile and web applications. Therefore, it is critical to protect the sensitive data they transfer. 

An API is an interface that defines how different software interacts. It controls the types of requests that occur between programs, how these requests are made, and the kinds of data formats that are used. APIs are used in Internet of Things (IoT) applications and on websites. They often gather and process data or allow the user to input information that gets processed within the environment housing the API. 

For example, there is an API that runs Google Maps. A web designer can embed Google Maps into a page they are building. When the user uses Google Maps, they are not using code the web designer wrote piece by piece, but they are simply using a prewritten API provided by Google. API security covers the APIs you own, as well as the ones you use indirectly.

Why Web API Security Is Important

Particularly with the rise of IoT, API security has become increasingly important. Crucial and sensitive data is transferred between users, APIs, and the applications and systems they interact with. An insecure API can be an easy target for hackers to gain access to an otherwise secure computer or network. Attackers may seek to perform man-in-the-middle (MITM), distributed denial-of-service (DDoS), injection, or broken access control attacks.

What is API?

An API is a mechanism that enables two software systems to interact. 

For example, the Google Maps application on a mobile device does not store all of the names of the streets, towns, cities, restaurants, movie theaters, and other landmarks in your phone. Instead, it connects to another application within the Google server that contains all of that information. This connection is made possible using an API.

REST API Security

Representational state transfer (REST) API security is one of the most common API securities available. With REST API security, you have a Hypertext Transfer Protocol (HTTP) Uniform Resource Identifier (URI), which controls which data the API accesses as it operates. REST API security can therefore prevent attacks involving malicious data an attacker is trying to introduce using an API.

How To Secure REST API

REST API supports secure sockets layer (SSL), transport layer security (TLS), and Hypertext Transfer Protocol Secure (HTTPS) protocols, which provide security by encrypting data during the transfer process. You can also secure REST APIs with tokens used to make sure communications are valid before allowing them to go through.

On the API level, security works by examining the data moving into the API environment. On the application level, API security blocks attempts to make the application malfunction or to allow other users to get inside and steal sensitive information.


Simple Object Access Protocol (SOAP) is a messaging protocol based on Extensible Markup Language (XML). It is used in the transfer of information between computers. It uses XML signatures and Security Assertion Markup (SAML) tokens to authenticate and authorize messages that get transferred. In this way, it provides API keys that prevent attackers from gaining access. 

The signatures and tokens have to match approved formats for the message to be allowed to pass through. REST is different from SOAP API security, particularly in that it does not require the routing and parsing of data. Instead, REST uses HTTP requests and does not require that data to be repackaged during the transfer process. 

Users may prefer to use SOAP over REST because SOAP services can be easier to design, and it is easier to operate SOAP across proxies and firewalls without modifying it first.

API Security Standards

It is crucial to protect data, particularly given the rise of data-dependent projects. The best way to secure APIs is to follow the API security best practices below.


API security begins with understanding the risks within your system. To identify weak points in the API lifecycle, you can look for specific vulnerabilities. For example, you can check for signature-based attacks like Structured Query Language (SQL) injections, use tighter rules for JavaScript Object Notation (JSON) paths and schemas, or use rate limits to provide protection for API backends.


Security tokens work by requiring the authentication of a token on either side of a communication before the communication is allowed to proceed. Tokens can be used to control access to network resources because any program or user that tries to interact with the network resource without the proper token will be rejected.


Encryption works by disguising data at one end of the communication and only allowing it to be deciphered at the other end if the proper decryption key is used. Otherwise, the encrypted data is a nonsensical jumble of characters, numbers, and letters. Encryption supports API security by making data unreadable to unauthorized users whose devices cannot decipher the data.

OAuth and OpenID Connect

Open authorization (OAuth) dictates how the client-side application obtains access tokens. OpenID Connect (OIDC) is an authentication layer that sits on OAuth, and it enables clients to check the identity of the end-user. Both of these work to strengthen authentication and authorization by limiting the transfer of information to only include those with either the appropriate, verifiable token or with the proper identification credentials.

Throttling and Quotas

Throttling and quotas protect bandwidth because they limit access to a system. Certain attacks, like DDoS assaults, seek to overwhelm a system. Throttling limits the speed at which data is transferred, which can thwart an attack that depends on a continual, quick bombardment of data. Quotas limit the amount of data that can be transferred, which can prevent attacks that leverage large quantities of data in an attempt to overwhelm a system’s processing resources.

API Gateway

An API gateway sits between the client and the collection of services specific to the backend. It serves the purpose of a reverse proxy, and as traffic passes through it, it is authenticated according to predetermined standards.

Zero-trust Approach

The zero-trust security model presumes that all traffic, regardless of whether it originates from within a network or from the outside, cannot be trusted. Hence, before traffic can be allowed to travel into or through the network, the user’s rights need to be authenticated. A zero-trust approach can provide security for data and applications by preventing unauthorized users from accessing a system—and this includes repeat users an imposter may impersonate using a previously authenticated device. In a zero-trust model, both the user and the device are untrusted.

What Are API Endpoints and Why Are They Important?

An API endpoint is the point at which an API communicates with another system—in other words, the URLs or digital locations the API uses to send data. API endpoints are important because they provide the exact location of the data or resources the API is accessing and ensure that the system communicating with the API is functioning optimally.

How Fortinet Can Help

A zero-trust model protects several elements of your network and its processes. These include data, applications, assets, and services. All of these can be manipulated or abused by a bad actor to try to compromise your network. For example, if an application has sensitive information, it may be an attacker's special target. Therefore, a zero-trust policy should be implemented when it comes to accessing that application’s resources. 

You also may have data that needs to be protected because an attacker may want to exploit, change, or steal it. Zero-trust security architecture used to shield this data can keep it safe from those who wish to take advantage of it, providing your organization with more thorough API protection.

It is important not to trust anything outside your security perimeter, and this includes systems and users within your network. Controlling access can keep attackers from penetrating your network and compromising APIs or their resources. 

FortiNAC is a zero-trust solution that limits network access. It gives users visibility into the various IoT devices that interact with their networks. With FortiNAC, you can limit access by requiring both users and devices to undergo authorization and authentication before being granted access. You can also profile users and devices to identify those that are safe and those that present a threat. FortiNAC automatically denies unsecured devices, which prevents hackers who are able to penetrate those devices from gaining a foothold in your network.

For many, FortiNAC also earns a top spot on their API security checklist because it can quarantine unsecured devices, preventing them from being abused by malicious users. In addition, FortiNAC provides your IT team with incident response options based on the enforcement of your organization’s security policies, thus making it a flexible solution suitable for a wide variety of network architectures and security strategies.