What is API Security?
An application programming interface, or API, is a critical innovation in a world driven by apps. APIs enable applications to communicate and share data while providing protocols, routines, and tools for software developers. They forge connections between applications, platforms and services such as databases, games, social networks, and devices. Internet of Things (IoT) devices and applications also use APIs to collect data, and sometimes even to control other devices.
Considering how essential they've become across the private and public sectors, APIs also present a rapidly expanding attack surface. And the reality is, they are often misunderstood and frequently overlooked by application security managers and software developers.
Exposed, faulty, broken, or hacked APIs are at the heart of many major data breaches. These attacks expose sensitive financial, medical, and personal data, leaving organizations on the hook. Even worse, many organizations essentially choose to run at a high risk, managing their APIs using the public cloud. This provides an ideal opportunity for attackers and points to the need for more consistent protection of API infrastructures.
With this in mind, the idea behind API security is to protect information transmitted by APIs. It involves having a deep understanding of the unique security risks and vulnerabilities APIs present. This includes exploring the impact of a successful attack. Once security teams understand this, they can create strategies for reducing those risks and generate solutions for incident response.
Why API security should be a top priority
API security controls are distributed between the delivery infrastructure, which includes API management, API gateways, and web application firewalls (WAFs). While there are other components in the stack, these are most relied upon for enforcing security policy and controls.
API Management and API Gateways
API management and API gateways play a very important role ensuring the delivery of APIs. Both are tightly linked together but shouldn't in anyway be confused with one another.
API management refers to the policies and processes involved in designing, publishing, and analyzing APIs. It also consists of monitoring usage and ensuring API availability. An API management system consists of four key components, such as: API Design, API Gateway, API Analytics, and an API Portal.
An API gateway on the other hand, is essentially a proxy with policy enforcement for API resources. It facilitates incoming traffic and enforces access controls. An API gateway operates in the data plane whereas an API management system operates at the control plane.
As the name suggests, API gateways serve as an access control point in front of an API endpoint. The API gateway provides core functionality to ensure the API is available to its intended consumers. The API gateway also is a control point for the API management policies such as access controls and usage (e.g. rate limiting and quotas).
Routing traffic through an API Gateway is a best practice, especially for open APIs exposed to the internet. However not all APIs sit behind a gateway. These APIs do not benefit from the controls and visibility provided by gateway and management functions.
Web Application Firewalls (WAFs)
Designed for web applications, WAFs have become part of the core stack for application and API protection. WAFs are proxy-based tools that inspect incoming http(s) web and API requests for attack or unwanted traffic. Like API gateways, a WAF can only apply policy to traffic that passes through it.
WAF capabilities vary, however the basic function is to provide an application layer filter for web and API traffic. This filter looks for malicious and unwanted content within incoming requests (headers and payloads). It is also used to ensure that only approved actions can be performed (by policy).
WAFs are utilized to provide basic protections for applications and APIs. They are fairly proficient at detecting known attacks (with signatures) and malicious scripts. Premium WAFs block automated scanners and bots, and provide broader coverage of the OWASP Top 10 for web apps.
Understanding API vulnerabilities
An API vulnerability is when an attacker can gain access to an API that has been left exposed to the internet. Or when they are able to modify data in the API without being authorized. This could be through entering information into an unprotected form field. Or by exploiting a code vulnerability in a web application that has been left open to the internet.
With that said, API design requires careful consideration of how data is stored, managed, accessed and transmitted. As APIs can handle sensitive data, it is important that the API design reflects the need for protection of this data. Failure to do so can result in a number of critical issues. Things like API key and credentials leaks, API code and schema exposure, and API infrastructure misconfigurations.
The most common API vulnerabilities are caused by flawed authentication methods or inadequate protection for sensitive data. For that reason, regulatory compliance is another concern for organizations. Especially for those whose APIs regularly handle personally identifiable information (PII), like credit cards, social security numbers, addresses, etc.
When you consider the types of sensitive data APIs interact with, addressing these threats becomes mission critical. But where do you start? The Open Web Application Security Project (OWASP) is a world renowned foundation that has documented the top API security risks. Known simply as the OWASP API Security Top 10, you can explore the API vulnerabilities that are most pressing.
Why traditional application security methods aren't enough
Quite frankly, security and developers teams need to accept that application security and API security are two different disciplines. This is the most obvious reason traditional AppSec tools fall short in protecting APIs. The primary difference is that application security protects the app itself. Whereas API security protects the APIs that are used to connect to other systems. Application security can also be referred to as "end-to-end" or "full stack" protection. Whereas API security is a part of it.
Application security is the measure of how secure an application is from attacks. It includes the security of data, network and hardware. API security, on the other hand, is about securing APIs from vulnerabilities and malicious attacks. API security focuses more on keeping attackers out. Either by creating secure designs for APIs, enforcing strong authentication and using encryption to protect data in transit.
API security controls are distributed between the delivery technology stack that includes API management, API gateways, and web application firewalls (WAFs). While there are other components in the stack, these are most notably relied upon for enforcing security policy and controls. Before we dive into why these tools are inferior, let's quickly discuss what they are and how they operate.
Key API security capabilities
A complete API security strategy is comprised of four key pillars. Each pillar contains specific security capabilities and goals in mind. These capabilities not only will help organizations monitor their APIs for any unusual activity or patterns of use. But they help protect against breaches, hackers, and other malicious activities. Let's review the pillars and what each entails below:
API discovery is a process of identifying every API you have and creating an accurate inventory of them. The objective here is to improve API visibility. As stated in the previous section, both API gateways and WAFs can only observe API traffic that is routed through them. Gartner predicts that 50% of enterprise APIs will be “unmanaged” by 2025 which means that visibility will be limited at best.
And while some unmanaged APIs are deployed on purpose, others may be unknown. The industry term for them are “shadow” or “zombie” APIs. These legacy and dormant APIs could be putting the organization at risk. Even if all APIs are routed through gateways and WAFs, most organizations will still struggle with visibility. API sprawl can span across multiple teams and business units, leaving security teams with a fragmented view of API usage.
API Security Posture Management
API posture management helps IT teams to quickly identify and resolve misconfigurations that could lead to a breach or compliance violations. Misconfigurations include: weak authentication, unknown exposure to the internet, and lack of rate limiting or encryption just to name a few.
Posture management also inspects contextual API data to find compliance risks. Contextual API data includes the types of data your APIs handle, like PII, credit card information, SSNs, etc. It also includes authentication controls, configurations, traffic and routing details, as well as exposure to the internet. It's important to note here that the combination API gateways and WAFs alone cannot provide detailed analysis of the API posture.
API Runtime Protection
Gateways and WAFs provide basic API security controls. Gateways can enforce rate limiting and authentication, while WAFs apply signature-based attack detection and appropriate user-based session behavior. These controls are very much needed but are not enough to protect the business from API specific attacks and abuse.
For example, broken object level authorization (BOLA) attacks look like normal API traffic to gateways and WAFs. And because they look normal, attacks are able to bypass these controls. Gateways and WAFs lack contextual awareness between API requests and responses. This this lack of contextual awareness can also leave you vulnerable other attacks and business logic abuse.
API Security Testing
API security testing is a crucial part of your API security strategy. It helps API developers uncover vulnerabilities, design flaws, and misconfigurations in the code before the APIs are released. To maximize their security testing efforts, many organizations have chosen to pursue a shift left strategy. Shift left is a popular practice where teams start their testing as early as possible. This ensures that any bugs are found and fixed early on, preventing them from being released to production.
It's important to keep in mind that API security testing is different from application security testing. It is also different from general API functionality testing, though API security testing should ideally be equally prioritized. Sometimes however, the two forms of testing overlap. For example, determining whether an API is returning the correct data is both functional and security related.
API security for SOAP, REST, and GraphQL
To keep them secure, it's important to understand the difference between the types of APIs you have. We'll review the three most prominent in use today – REST, SOAP, and GraphQL. REST stands for Representational State Transfer. It is an architecture style that defines a set of constraints for creating scalable and efficient web services.
REST APIs are the most popular type of API and use HTTP methods to communicate between client and server. HTTP verbs like GET, POST, PUT, and DELETE are applied in order to manipulate data. A REST API is built on the principles of the REST architecture. However they go a step further by enforcing a strict separation between the client and server. They are simple and easy to use, but they lack security features.
SOAP, or Simple Object Access Protocol, is an XML-based protocol for exchanging messages between applications over HTTP. SOAP APIs are usually used to integrate legacy systems with newer ones, but are more difficult to use than REST APIs. It's also important to note that despite SOAP APIs being , they do offer more security features.
SOAP is typically used by web services that need more security because it provides features like authentication and encryption. In comparison, with a REST API, authentication can be done through URL parameters or headers only.
GraphQL is a data query language developed by Facebook in 2012 and open-sourced in 2015. GraphQL APIs allow clients to specify what data they need from the server rather than fetching all available data from it. GraphQL is gaining popularity because it is easier to use than REST and SOAP APIs, yet it offers more security features.
Addressing security across the API ecosystem
Everyone wants secure APIs. But the process is complex and requires an approach that considers all aspects of the API. From its development, deployment configuration, and run-time operations. Though there are a number of API security best practices, they generally fall into one of the three following areas:
- API security posture. Assess every API, including legacy and shadow APIs, and uncover the types of data they encounter. Based on that inventory, identify misconfigurations and vulnerabilities in the source code, network configuration, and policy. Focus security interventions on the highest-risk areas.
- Detection and response. Deploy behavioral AI models for real time API threat detection. Integrate with with existing IT workflows to automate incident response and block serious threats.
- Continuous testing. Continuously test API endpoints to identify API risks before they emerge. Supplement DevOps DAST, SAST, SCA and other existing tools with API security testing that can be automated and integrated into CI/CD pipelines. Adequate testing will help you discover design flaws and prevent attacks like SQL injections.
If you're looking for more detailed guidance, we recommend taking a look at our API security checklist here. It provides a detailed framework of API security requirements you need to protect your environment.
Frequently Asked Questions
1. What security measures should I take to protect my API?
There are several security measures you should take to protect your API:
Implement authentication for your API: Authentication is the process of verifying the identity of a user in order to allow access to the API. You can enable authentication through a variety of protocols such as OAuth, OpenID Connect, or API keys.
Implement authorization for your API: Authorization is the process of granting or denying access to specific resources within the API. You can enable authorization by using roles, permissions, or other access control methods.
Enable API key management: API keys are a great way to secure your API and prevent unauthorized access. It is important to have a robust API key management system in place to ensure that API keys are securely stored and regularly rotated.
Monitor and detect API abuse: API abuse can be difficult to detect, so it is important to monitor your API traffic and detect any suspicious activity. You can use API analytics or security solutions to help you monitor and detect API abuse.
Secure data: It is important to ensure that any data being transferred through your API is securely encrypted. You can use TLS or SSL to encrypt data in transit.
Monitor API performance: It is important to monitor the performance of your API to ensure that it is running optimally and that there are no vulnerabilities. You can use API analytics or performance monitoring tools to help with this.
Keep your API up-to-date: It is important to keep your API up-to-date with the latest security patches and updates. This will help to ensure that your API is secure and protected against any potential vulnerabilities.
2. How do I identify and prevent malicious API requests?
Protecting your API from malicious requests is essential for maintaining the security and integrity of your data. Here are some tips on how to identify and prevent malicious API requests:
1. Monitor API Activity
Monitoring your API activity is a great way to identify any suspicious requests. You can use analytics tools to monitor your API traffic and detect any abnormal or malicious requests. This will help you identify any suspicious activity and take appropriate action.
2. Implement Rate Limiting
Rate limiting is a great way to prevent malicious requests and protect against abuse. With rate limiting, you can set rules on how many requests a user can send in a certain time period. This will help to prevent malicious requests from flooding your API and potentially causing damage.
3. Use Whitelisting
Whitelisting is a great way to protect your API from malicious requests. With whitelisting, you can specify which IP addresses or domains are allowed to access your API and block any requests from unauthorized sources.
4. Use Firewalls
Firewalls are a great way to protect your API from malicious requests. A firewall will help to filter out any suspicious requests and block them from entering your system. This will help to protect your system from potential threats and keep your data secure.
5. Implement Encryption
Encryption is a great way to protect your data from malicious requests. Implementing encryption will help to ensure that any data transferred through your API is securely encrypted and protected from any potential threats.
3. How can I secure my API from unauthorized access?
Securing your API from unauthorized access is essential for maintaining the security and integrity of your data. Here are some tips on how to secure your API from unauthorized access:
1. Implement Authentication
Implementing authentication is one of the most effective ways to secure your API from unauthorized access. Authentication is the process of verifying the identity of a user in order to allow access to the API. You can enable authentication through a variety of protocols such as OAuth, OpenID Connect, or API keys.
2. Implement Authorization
Implementing authorization is another effective way to secure your API from unauthorized access. Authorization is the process of granting or denying access to specific resources within the API. You can enable authorization by using roles, permissions, or other access control methods.
3. Enable API Key Management
API keys are a great way to secure your API and prevent unauthorized access. It is important to have a robust API key management system in place to ensure that API keys are securely stored and regularly rotated.
4. Implement Encryption
Encryption is a great way to protect your data from unauthorized access. Implementing encryption will help to ensure that any data transferred through your API is securely encrypted and protected from any potential threats.
5. Monitor API Activity
Monitoring your API activity is another great way to secure your API from unauthorized access. You can use analytics tools to monitor your API traffic and detect any suspicious requests. This will help you identify any unauthorized access attempts and take appropriate action.
4. What are the best practices for API key management?
API key management is an important part of securing your API. Here are some best practices for API key management:
1. Store Keys Securely
It is important to store API keys securely to prevent unauthorized access. You can store API keys in an encrypted database or file system and make sure that the keys are not accessible to anyone else.
2. Rotate Keys Regularly
It is important to rotate API keys regularly to prevent unauthorized access. You can set up a rotation schedule and automate the process of generating and deleting keys. This will help to ensure that your keys are secure and up-to-date.
3. Monitor Key Usage
It is important to monitor API key usage to detect any suspicious activity. You can use analytics tools to monitor key usage and detect any malicious requests. This will help you to identify any potential threats and take appropriate action.
4. Revoke Keys Immediately
It is important to revoke API keys immediately if they are compromised or no longer needed. You can use an automated process to revoke keys and ensure that they are not used again.
5. Use Strong Passwords
It is important to use strong passwords for your API keys. You can use a combination of upper and lowercase letters, numbers, and special characters to create a strong and secure password.
5. How can I monitor and detect API abuse?
Monitoring and detecting API abuse is essential for maintaining the security and integrity of your API. Here are some tips on how to monitor and detect API abuse:
1. Monitor API Traffic
Monitoring your API traffic is a great way to identify any malicious requests. You can use analytics tools to monitor your API traffic and detect any abnormal or malicious requests. This will help you identify any suspicious activity and take appropriate action.
2. Implement Logging
Implementing logging is a great way to monitor and detect API abuse. With logging, you can track all requests made to your API and detect any suspicious activity. This will help you identify any malicious requests and take appropriate action.
3. Use IP Blocking
IP blocking is a great way to detect and prevent API abuse. With IP blocking, you can specify which IP addresses or domains are allowed to access your API and block any requests from unauthorized sources.
4. Use Security Solutions
Security solutions are a great way to detect and prevent API abuse. Security solutions can help to detect any malicious requests and take appropriate action to protect your API from abuse.
5. Use Intrusion Detection Systems
Intrusion detection systems are a great way to detect and prevent API abuse. Intrusion detection systems can help to detect any malicious requests and take appropriate action to protect your API from abuse.