API Security 2023: Understanding Best Practices to Mitigate Threats

What is API security all about in 2023., and what are some of the best practices?

a year ago   •   6 min read

By Davor Kolenc
Table of contents

APIs (Application Programming Interfaces) have been crucial for businesses to facilitate distributed systems. They help organizations build a decoupled architecture using different services, all communicating through APIs. Not just services, APIs can connect different systems and applications, allowing them to communicate with each other.

APIs facilitate data sharing between heterogeneous systems where hackers try to attack. Cyber attackers target APIs to access systems using them as entry points. API security breaches can lead to data theft, financial fraud, and malicious activities.

According to a survey, 41% of organizations faced an API security incident leading to a data breach in 2021. So, API security becomes crucial for businesses to ensure a secure customer experience.

Here we will discuss API security, how to deal with different threats to APIs and best practices for handling them.

Understanding API Security

API security is a set of processes and practices organizations use to protect their systems from unauthorized access and misuse. It includes authentication, authorization, and encryption mechanisms to control access and protect data integrity.

So, security becomes crucial if you use a distributed system with several services communicating through APIs. Let’s first understand what an API is briefly.

What is API security?

API security is the practice of protecting your APIs from unauthorized access. Systems communicate with each other through APIs, and that is why it becomes crucial to secure them. One of the most common cyber threats APIs experience is malicious code injections.

Due to malicious code executions triggered through system activity or a user request, hackers can access sensitive information. Let’s understand how exactly hackers attack your APIs.

How do APIs get attacked?

One common way cyber attackers can access a secure API is by compromising the authentication mechanisms. This is a significant API security threat, where attackers access user information stored in the system.

Another significant API security threat is cross-site scripting (XSS), where an attacker injects malicious code into a web page. When these users access the page, the code in question executes automatically. It can take unexpected actions on their behalf, such as running unwanted scripts or stealing information from their browsers.

Many organizations deploy various security measures to protect APIs from unauthorized access. These include restricting user access to specific functions within an API, implementing authentication mechanisms, and monitoring for malicious activity targeting the API.

However, XSS is not the only API security threat; there are many others, like

Injection Attacks

An injection attack is one of the most common API security threats. Cyber attackers use it to gain unauthorized access to protected APIs. With an injection attack, an attacker tricks a user into entering malicious code directly into the API interface.

This can be done in several ways, including

  • Injecting SQL statements or script files directly into the API response packet
  • Poisoning popular request headers with unexpected values, known as header injections.
  • Exploiting known vulnerabilities in web applications that allow remote attackers to inject arbitrary JavaScript code.

Broken Authentication and Authorization

One of the most common ways attackers access secure APIs is through broken authentication and authorization. An attacker uses social engineering practices to gain vital user credentials.

Then,  attackers use these credentials to impersonate authorized users within the system. This gives them unrestricted access to resources owned by that particular user and potentially sensitive information stored on behalf of other users in that organization.

Denial of Service (DoS) attacks

A DoS attack disrupts the functionality of a system or network by flooding it with requests that are too large for the resources to handle. A common type of DoS attack is called Request Forgery (RF). In RF attacks, attackers use social engineering to trick users and place a request to access secure systems on their behalf.

This request then overloads the server and prevents legitimate requests from being handled. Due to the flooding of requests, application performance degrades for all users who try to access the affected resource.

Now that we know your systems' threats, here are some API security best practices to follow.

Best Practices for API Security

Verifying user credentials before allowing them access to specific functions within an API is a fundamental API security best practice to follow. However, many other best practices exist, like implementing session management policies, developing a framework, or establishing authentication mechanisms to secure apps.

Develop an API security threat model

An API security threat model helps understand how potential security threats may affect your systems. It provides a framework for anticipating and understanding how attacks might attempt to exploit vulnerabilities, ultimately affecting infrastructure, products, processes, and people.

The API security threat model allows organizations to analyze their exposure to attacks targeting APIs. Further, it helps ensure appropriate measures are in place to protect themselves from these risks.

The following are some common elements that could be included in the API security threat model:

  • Vulnerabilities in the authentication mechanisms used by an API
  • Insecure communications protocols used by an API
  • Insufficient security controls on data stored or transmitted by an API
  • Weaknesses in the architecture of an organization that could lead to unauthorized access to its systems through APIs

Authentication and Authorization

Data authentication and authorization are critical to ensure that data access privileges are not abused. You can leverage multi-factor authentications to ensure user credentials are not misused.

For example, you can use two-factor authentication for API security. Users with access privileges to internal and external APIs should be asked to use two-factor authentication. In two-factor authentication, users must provide their credentials with a passcode or one-click sign-in through a message delivered on a personal device.


You can use encryptions to ensure API security. The best way to encrypt APIs is to use code-signing certificates. You can get a code signing certificate from the certificate authority (CA) by submitting a certificate signing request (CSR).

Once submitted, CA validates the information in CSR and issues the certificate you can install on applications to secure APIs.

Input validation and output encoding

Input validation checks whether incoming data is appropriately formatted. At the same time, output encoding ensures that the information sent from an API is safe to display publicly.

For example, if an API sends the user name and password information in plaintext form, it can be a cybersecurity risk. Attackers can exploit user credentials and access sensitive data. Encoding this data will make it difficult for someone to decode and use this sensitive information.

Rate Limiting

Rate limiting is an API security best practice where you can limit the number of requests an individual user can make per minute. This prevents an attacker from abusing the API to flood it with traffic, causing the system to become congested.

It also helps to prevent unwanted automated actions from being carried out. Take the example of an eCommerce application exposing an API for users to place orders, check order status, and perform other actions. You can implement rate limiting to restrict the number of requests a user can make within a specific time period to prevent API abuse.

What is the future of API security?

As the API ecosystem continues to grow and evolve, API security will likely remain a priority for organizations. As more companies develop their APIs, protecting them from unauthorized access becomes even more critical.

In addition, continued technological advances will make it easier for attackers to exploit vulnerabilities in APIs. 5G connectivity is a fine example of how improved technology can challenge API security. With improved networks and faster connectivity, IoT devices will need enhanced API security.

If IoT API is not secure, attackers can access the networks and sensitive information. This is why having an API security threat model becomes crucial to ensure advanced visibility and plan your cybersecurity measures accordingly.


API security is one of the most important aspects of data protection. Understanding and mitigating API threats can help protect your data from cyberattacks. This blog has outlined some of the most common threats and how to protect your systems using API security best practices. However, which best practice to use depends on specific business needs.

So, it is crucial to analyze your applications and business requirements to design an API security threat model.

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