/ Unified Security Guide / Chapter 5: API security

API security

In today’s app-driven world, application programming interfaces (APIs) are critical components of modern application architecture. APIs—or software intermediaries that facilitate communication between applications or other services—provide modular application architectures that allow capabilities and information from an app to be shared and used by other apps.

Because APIs are increasingly featured in modern mobile and web applications—including enterprise-level applications that are utilized by employees, partners, or customers—ensuring that APIs are secured has never been more important.

By design, APIs expose application workflows and sensitive data, which has made them an increasingly popular target for bad actors. According to Gartner, by 2022, API abuses will become the most-frequent attack vector. Weak authentication protocols and encryption, server misconfigurations, and unsecure endpoints are all common types of API vulnerabilities that could lead to attacks like:

Man in the middle (MITM) attacks

An attacker intercepts a conversation or data transfer between two parties and impersonates both parties. This allows them to steal sensitive information from or send malicious links to either party.

API injections

An attacker inserts malicious code or commands into a vulnerable program to stage an attack, such as a cross-site scripting (XSS) or Structured Query Language (SQL) injection attack.

Distributed denial of service (DDoS)

An attacker floods an API endpoint with more traffic than it can handle, which renders it unavailable to legitimate to users.

As the complexity of application environments evolve—be it from shifting applications from on-premises data centers to one of multiple cloud platforms or developing new applications using microservices-based architectures—APIs are key to ensuring a scalable and modular application architecture. Frequently, organizations attempt to secure their APIs by deploying disparate security solutions, which ends up leaving their attack surface exposed and vulnerable.

To ensure your organization’s APIs stay protected against modern-day cyber threats, it’s important to learn how to properly secure them. Below, we will break down API security best practices, as well as holistic API security solutions you can start implementing today.

What are API security best practices?

Illustration of the best practices for API security.

API security best practices start with authentication, authorization, encryption, and API inventory:

01 Authentication and Authorization: APIs act as an entry point to an organization’s databases, which means it’s crucial to implement the proper authentication and authorization methods to control access to them. Authentication proves that a client accessing an API is really who it says it is, and authorization is verifying that the client has the right to access the data it is asking for.

02 API Gateway Security: These gateways also play an important role in API authentication and authorization. Through industry-standard encryption and access controls, robust API gateway security verifies the identity associated with API requests through authentication means like credential and token validation. They can also determine which traffic is authorized to pass through the API to backend services.

03 TLS/SSL Encryption: If your APIs exchange sensitive data or personally identifiable information (PII)—such as login credentials, credit card numbers, social security numbers, banking information, or health information—encrypting all transmitted data will help mitigate threats.

04 API Inventory: Regularly taking inventory of your organization's APIs is another important strategy for API security. With the rise in shadow APIs—or third-party APIs that your organization uses but does not track or control—bad actors are finding open doors to steal sensitive data or compromise enterprise apps.

05 API Key Storage: API keys should not be stored in public cloud storage like Amazon S3 or code repositories like GitHub, as they are publicly available. Be sure your organization also performs regular code reviews so that no hard-coded API keys make their way into applications.

How to secure your APIs

While a common approach to secure a traditional monolithic API includes using an appliance-based WAF or DDoS protection, modern API-based apps require a solution that is cloud delivered and can provide protection in a multi-cloud or hybrid cloud environment.

Illustration of a laptop and how to secure your API.

Most existing API security solutions can’t mitigate modern DDoS attacks, especially volumetric DDoS attacks. As on-premises API security appliances are limited in scalability, these attacks can easily overwhelm an appliance-based solution.

Modern API security solutions should consistently enforce authentication authorization, as well as ensure comprehensive protection that supports an always-on security framework across multi-cloud setups.

Holistic API security solutions

Modern, holistic API security solutions should use AI and machine learning (ML) to continuously adapt to changing API threats, especially in multi-cloud environments. They should also provide unified API management to ensure easy scalability and that your organization has an always-on, centralized security posture. Functionality of a holistic API security solution should include:

  • Security for monolithic and microservice-based APIs.
  • Botnet mitigation and prevention.
  • WAF integration to shield against XSS attacks and SQL injections.
  • Automated API inventory management.
  • API security and performance analytics, as well as Abuse detection.
  • Protection against JSON- and XML-based threats and buffer overflows.
  • Volumetric DDoS protection, including protection against Layer 4-7.
  • Centralized and easily configurable security policy management.
  • A unified API security management dashboard with visibility into security governance across multi-cloud environments.
  • Low latency and consistent protection for APIs, no matter where they are deployed.

Web app and API protection with Citrix

Citrix provides a comprehensive on-premises or cloud-delivered security solution that offers robust app and API security regardless of architecture (including monolithic or microservices-based frameworks) or where APIs are deployed across your multi-cloud environment. This solution includes authentication authorization, encryption, rate limiting, and the discovery and inventory of APIs. With Citrix, you gain access to:

  • App and API protection against OWASP Top 10 and zero-day attacks using bot mitigation, an integrated Web Application Firewall, and volumetric DDoS protection.
  • A simple set up process and easy scalability to help you achieve a consistent security posture across all your organization's apps and APIs.
  • A single code base that provides holistic security policy control and visibility from a single pane of glass.
  • Governance and compliance requirements, including PCI-DSS.

Using Citrix ADC and Citrix Application Delivery Management, you can easily strengthen your app and API security through tools like customizable API gateways and always-available analytics.

  • Citrix ADC: Incorporates API gateway functionality to provide a single point of entry for API calls. It can also perform rate limiting, authentication and authorization, and content routing to ensure secure, reliable access to backend services via your APIs.
  • Citrix Application Delivery Management: Utilizes AI and machine learning to mitigate modern cyberattacks, including excessive client connections via API and attempted account takeovers. Citrix also provides always-available security analytics, so you can keep an eye on WAF or bot violations.

Elevate your API security with Citrix

APIs are essential components of enterprise applications and keeping them secure—especially as you shift to multi-cloud environments and grow your remote workforce—is more important than ever. Cybercriminals continue to target vulnerable APIs to steal data or sensitive information, compromise intellectual property, or deploy malicious links.

Fortunately, with web app and API protection from Citrix, you can secure your apps and APIs quickly without dealing with infrastructure complexities. Featuring user-friendly dashboards and centralized control, we make it simple and intuitive to configure your app and API security policies across your entire multi-cloud environment. It also features a low barrier to entry, which means IT teams won’t require additional skill sets to properly secure your infrastructure.


How do I secure web APIs?

Modern, cloud-focused API security solutions should consistently enforce authorization and authentication, as well as ensure comprehensive protection that supports an always-on security framework across multi-cloud setups. To this, you must deploy robust volumetric distributed denial of service (DDoS) protection, bot mitigation solutions, and an advanced web application firewall (WAF).

What are API security best practices?

API security best practices include authorization and authentication management, TLS/SSL encryption, advanced API gateways, and regular API inventory to control shadow APIs.

How do I secure an API without authentication?

Authentication is an important aspect to API security, as identifying the identity of your end users is critical to ensuring bad actors aren’t attempting to exploit your APIs