How To Secure APIs: Best Practises
API stands for Application Programming Interface. It is a set of protocols, routines, and tools for building software applications. APIs define the way in which two software systems interact with each other.
In simpler terms, an API is a messenger that delivers a request from one software application to another and returns the response back to the requester. The request and response usually take the form of a data format, such as JSON or XML.
APIs can be used to retrieve data from a remote system, send data to a remote system, or perform some other action on a remote system. For example, social media platforms like Facebook and Twitter provide APIs that allow developers to retrieve data such as user profiles, posts, and comments.
APIs have become increasingly important in today’s digital world, as they allow different software applications and systems to communicate with each other seamlessly. This has opened up new opportunities for businesses to integrate their systems and services with other systems and services, leading to increased efficiency, improved customer experiences, and new business opportunities.
Table Of Contents
- 1. Types of APIs
- 2. What Is API Security?
- 3. Why API Security Is Important?
- 4. Common API Security-Related Attacks
- 5. Practises to Secure APIs
- 6. API Security Testing Standards
- 7. Conclusion
1. Types of APIs
- Web APIs: These are APIs that are accessed over the internet using HTTP. Web APIs can be divided into two types: REST APIs and SOAP APIs.
- REST APIs: REST (Representational State Transfer) APIs are the most common type of web API. They use HTTP methods like GET, POST, PUT, and DELETE to interact with resources (like data) on a server.
- SOAP APIs: SOAP (Simple Object Access Protocol) APIs are a type of web API that uses XML as the message format and HTTP or HTTPS for transport.
- GraphQL APIs: GraphQL is a newer API technology that allows clients to specify exactly what data they need, reducing the amount of data that needs to be transferred.
- Operating System APIs: These are APIs that provide access to system resources on a device or computer, like the file system or network connections.
- Library APIs: These are APIs that are included in a software library or framework and provide pre-written functionality that developers can use in their applications.
- Class APIs: Class APIs are specific to object-oriented programming languages and provide access to a specific class of objects.
- Database APIs: These are APIs that provide access to a database, allowing developers to create, read, update, and delete data.
- Cloud APIs: Cloud APIs provide access to cloud-based services, like storage, computing, or machine learning, allowing developers to build applications that use these services.
2. What Is API Security?
API security refers to the measures taken to secure application programming interfaces (APIs) from unauthorized access and malicious attacks. An API is a set of protocols and standards used for building software applications, and it allows different systems and applications to communicate with each other.
API security involves ensuring that only authorized users or systems can access and use the API, preventing attacks such as injection attacks, cross-site scripting (XSS) attacks, and other types of exploits. It also involves protecting the confidentiality, integrity, and availability of data transmitted through the API.
API security can be achieved through a combination of authentication, access control, encryption, monitoring, and other security measures. API providers must take appropriate measures to ensure the security of their APIs, as any security vulnerabilities can potentially result in the loss of sensitive data, financial loss, or damage to the reputation of the organization.
3. Why API Security Is Important?
API security is important for several reasons, including:
- Protection of sensitive data: APIs can transmit sensitive data such as personal information, financial data, and other confidential information. If this data falls into the wrong hands, it can lead to significant financial loss, legal liabilities, and damage to the reputation of the organization.
- Preventing unauthorized access: APIs can be accessed by both authorized and unauthorized users. Unauthorized access can lead to data breaches, denial-of-service attacks, and other malicious activities.
- Compliance: Many industries are subject to regulations such as HIPAA, PCI-DSS, and GDPR, which require organizations to protect sensitive data and ensure that only authorized users have access to it. APIs must be secured to ensure compliance with these regulations.
- Protecting intellectual property: APIs can be used to access proprietary software and data, and it’s essential to protect these assets from unauthorized access and theft.
- Maintaining business continuity: Malicious attacks on APIs can disrupt business operations, leading to downtime and financial loss. API security helps to prevent such attacks and ensure business continuity.
In summary, API security is essential to protect sensitive data, prevent unauthorized access, comply with regulations, protect intellectual property, and maintain business continuity.
4. Common API Security-Related Attacks
There are several common API security-related attacks, including:
- Injection attacks: Injection attacks occur when an attacker sends malicious input to an API with the intent of executing unauthorized code or accessing sensitive data. Examples of injection attacks include SQL injection and command injection.
- Cross-site scripting (XSS) attacks: XSS attacks occur when an attacker injects malicious scripts into a web application or API, which can be executed by unsuspecting users who visit the site or use the API.
- Denial-of-service (DoS) attacks: DoS attacks are designed to overwhelm an API with requests, causing it to become unavailable to legitimate users.
- Broken authentication and session management: These attacks occur when authentication and session management mechanisms are poorly implemented, allowing attackers to gain unauthorized access to the API.
- Insufficient encryption: If sensitive data transmitted through an API is not encrypted, it can be intercepted by attackers and used for malicious purposes.
- API key theft: API keys are often used to authenticate and authorize access to APIs. If these keys are stolen or compromised, an attacker can gain unauthorized access to the API.
- Man-in-the-middle attacks: Man-in-the-middle attacks occur when an attacker intercepts communication between an API and a client, allowing them to view and modify the data being transmitted.
- Cross-site request forgery (CSRF) attacks: CSRF attacks occur when an attacker tricks a user into performing an unintended action on an API by exploiting the user’s authenticated session.
It’s essential to protect APIs against these and other types of attacks by implementing appropriate security measures such as authentication, access control, encryption, and monitoring.
5. Practises to Secure APIs
Here are some best practices for securing APIs:
- Authentication and Authorization: Use authentication and authorization mechanisms to verify the identity of users and their access privileges. Use strong authentication mechanisms like OAuth 2.0, OpenID Connect, or JWT (JSON Web Tokens) to ensure secure authentication.
- Encryption: Use strong encryption mechanisms like SSL/TLS to secure communication between the API and the client, and to protect sensitive data transmitted through the API.
- Access control: Use access control mechanisms like role-based access control (RBAC) or attribute-based access control (ABAC) to control access to APIs based on user roles, permissions, and attributes.
- Input validation: Validate all input data received by the API to prevent injection attacks, cross-site scripting (XSS) attacks, and other types of exploits.
- Output filtering: Filter all output data returned by the API to prevent XSS attacks and other types of exploits.
- Error handling: Implement proper error handling mechanisms to prevent information disclosure and to provide meaningful error messages to users.
- Monitoring: Monitor the API for suspicious activity and anomalies. Use log analysis and real-time monitoring to detect and respond to security incidents.
- Versioning: Use versioning mechanisms to ensure backward compatibility and to prevent security issues caused by breaking changes.
- Regular updates and patches: Keep the API and its dependencies up-to-date with the latest security patches and updates to prevent vulnerabilities.
- Security testing: Conduct regular security testing and vulnerability assessments to identify and address security weaknesses in the API.
By following these best practices, organizations can ensure the security and integrity of their APIs, protect sensitive data, and prevent malicious attacks.
6. API Security Testing Standards
API security testing standards are guidelines and best practices for testing the security of APIs. These standards help ensure that APIs are tested consistently and thoroughly, and that all relevant security risks are identified and addressed.
Here are some of the most widely recognized API security testing standards:
- OWASP API Security Testing Project: The OWASP API Security Testing Project is a comprehensive guide to testing the security of APIs, and includes detailed testing procedures and checklists.
- NIST SP 800-53: This is a standard developed by the National Institute of Standards and Technology (NIST) that provides guidelines for information security and risk management, including security testing for APIs.
- ISO/IEC 29147: This is an international standard for vulnerability disclosure, and includes guidelines for conducting security testing of APIs and reporting vulnerabilities.
- NIST SP 800-115: This is a guide to conducting penetration testing, which includes specific guidance for testing APIs.
- OpenAPI Specification (OAS) 3.0: This is a standard for defining and documenting APIs, and includes guidelines for security testing and vulnerability management.
In addition to these standards, there are also a number of tools and frameworks available for API security testing, such as OWASP ZAP, Burp Suite, Postman, and RestAssured.
6.1 Open Web Application Security Project (OWASP) API
The Open Web Application Security Project (OWASP) API Security Project is a community-driven initiative focused on improving the security of APIs. The project provides resources, tools, and guidance to help organizations secure their APIs against common vulnerabilities and attacks.
The OWASP API Security Project includes a set of guidelines and best practices for API security, called the OWASP API Security Top 10. These guidelines cover the most common API security risks, including injection attacks, broken authentication and session management, and insufficient logging and monitoring.
The OWASP API Security Project also provides a number of tools and resources for API security, including the OWASP API Security Testing Framework, which is designed to help organizations test the security of their APIs, and the OWASP API Security Cheat Sheet, which provides practical advice for securing APIs.
In addition to these resources, the OWASP API Security Project hosts community events and provides opportunities for developers, security professionals, and others to collaborate and share knowledge on API security.
The OWASP API Security Top 10 is a list of the most critical security risks to APIs, based on input from security experts and industry practitioners. The Top 10 list is intended to help organizations identify and address common API security risks.
Here are the OWASP API Security Top 10:
- Broken Object Level Authorization: This occurs when an API fails to properly enforce access controls on individual objects or data fields. As a result, attackers may be able to access sensitive data or modify it in unauthorized ways.
- Broken Authentication and Authorization: This occurs when an API’s authentication and authorization mechanisms are not implemented correctly, allowing attackers to gain unauthorized access to the API or its data.
- Excessive Data Exposure: This occurs when an API returns too much data in its responses, exposing sensitive data that should not be made available to unauthenticated or unauthorized users.
- Lack of Resources and Rate Limiting: This occurs when an API does not implement proper rate limiting or resource management, making it vulnerable to denial-of-service (DoS) attacks and other types of abuse.
- Broken Function Level Authorization: This occurs when an API fails to properly enforce access controls on individual API functions or endpoints, allowing attackers to access sensitive functionality or data.
- Mass Assignment: This occurs when an API allows users to submit additional parameters to an API request, potentially allowing attackers to modify data that should not be modifiable.
- Security Misconfiguration: This occurs when an API is not configured securely, leaving it vulnerable to attacks such as injection attacks and DoS attacks.
- Injection Attacks: This occurs when an attacker sends malicious input to an API with the intent of executing unauthorized code or accessing sensitive data.
- Improper Assets Management: This occurs when an API fails to properly manage and protect sensitive data assets, such as API keys and credentials.
- Insufficient Logging and Monitoring: This occurs when an API does not log and monitor events and activities, making it difficult to detect and respond to security incidents and attacks.
By addressing these top 10 API security risks, organizations can better protect their APIs and the sensitive data they handle, and reduce the risk of security incidents and breaches.
6.2 NIST SP 800-53
NIST SP 800-53 is a special publication developed by the National Institute of Standards and Technology (NIST) that provides guidelines for security and privacy controls for federal information systems and organizations. The publication is titled “Security and Privacy Controls for Federal Information Systems and Organizations” and is widely used as a framework for information security in the United States federal government, as well as in other organizations.
The publication includes a comprehensive set of security controls that can be used to protect information systems and sensitive data from a wide range of security threats. These controls cover a wide range of security areas, including access control, contingency planning, incident response, risk assessment, system and communications protection, and security assessment and authorization.
NIST SP 800-53 is designed to be flexible and adaptable, and can be customized to meet the specific security needs of different organizations and information systems. The guidelines are technology-neutral and are designed to be applicable to a wide range of information systems and environments, including cloud computing, mobile devices, and IoT devices.
The publication is regularly updated to reflect new security threats and emerging technologies. The most recent version, NIST SP 800-53 Rev. 5, was released in September 2020 and includes new controls and updates to existing controls to address emerging threats such as supply chain risk management, identity and access management, and privacy.
6.3 ISO/IEC 29147
ISO/IEC 29147 is an international standard that provides guidelines for vulnerability disclosure. The standard is titled “Information technology — Security techniques — Vulnerability disclosure” and provides a framework for identifying and reporting vulnerabilities in information technology products and services.
The standard provides guidance on the following topics:
- Identifying vulnerabilities: The standard provides guidance on how to identify vulnerabilities in information technology products and services. This includes both technical and non-technical methods for identifying vulnerabilities.
- Reporting vulnerabilities: The standard provides guidance on how to report vulnerabilities to the vendor or service provider. This includes guidelines for the content of the report, the format of the report, and the methods for submitting the report.
- Handling of vulnerability reports: The standard provides guidance on how vendors and service providers should handle vulnerability reports. This includes guidelines for the initial response, the investigation of the vulnerability, and the development and distribution of a patch or workaround.
- Coordination of vulnerability disclosure: The standard provides guidance on how to coordinate vulnerability disclosure between the vendor or service provider, the researcher who discovered the vulnerability, and any other stakeholders. This includes guidelines for the timing of the disclosure and the communication between the parties involved.
6.4 NIST SP 800-115
NIST SP 800-115 is a document published by the National Institute of Standards and Technology (NIST) that provides guidelines for implementing the technical security controls required by the Federal Information Security Management Act (FISMA).
The document, titled “Technical Guide to Information Security Testing and Assessment,” outlines the process of testing and assessing the security controls of information systems. It provides guidance on how to plan, conduct, and report on security tests and assessments, including vulnerability scanning, penetration testing, and security control assessments.
NIST SP 800-115 is intended for use by security professionals, including IT managers, security auditors, and penetration testers. It is part of a larger set of guidelines and standards developed by NIST to help federal agencies and organizations secure their information systems and protect against cyber threats.
6.5 OpenAPI Specification (OAS) 3.0
The OpenAPI Specification (OAS) is a widely-used standard for defining RESTful APIs. OAS 3.0 is the latest version of the specification and was released in 2017. It includes several new features and improvements over the previous version (OAS 2.0), including:
- Components: OAS 3.0 introduces a new components section, which allows developers to define reusable, modular components that can be used throughout their API definition. This can help reduce redundancy and make it easier to maintain and update APIs.
- OneOf and AnyOf: OAS 3.0 introduces new keywords for defining conditional schemas. The OneOf keyword is used to specify that a property must match exactly one of several possible schemas, while the AnyOf keyword specifies that a property can match any of several possible schemas.
- Callbacks: OAS 3.0 introduces a new callbacks section, which allows developers to define callbacks that can be triggered by specific events in the API. This can be useful for implementing real-time or push-style APIs.
- Security Schemes: OAS 3.0 introduces several new security schemes, including OAuth 2.0 and OpenID Connect. It also introduces support for mutual TLS (mTLS) authentication.
- Links: OAS 3.0 introduces a new links section, which allows developers to define links between different resources in their API. This can help make APIs more discoverable and easier to navigate.
Securing APIs is an essential aspect of overall application and system security. APIs are increasingly being used to share data and functionality between different applications and systems, making them a prime target for attackers. As such, organizations need to implement best practices for API security, such as authentication and authorization, encryption, access control, input validation, output filtering, error handling, monitoring, versioning, regular updates and patches, and security testing.
The OWASP API Security Top 10 provides a useful framework for identifying and addressing the most critical security risks to APIs. By following these guidelines and implementing best practices for API security, organizations can protect their APIs against common vulnerabilities and attacks, and safeguard sensitive data from unauthorized access or modification.
Overall, securing APIs requires a multi-layered approach that involves designing and developing secure APIs, implementing strong authentication and access controls, monitoring for suspicious activity, and conducting regular security testing and assessments. By taking these steps, organizations can ensure the security and integrity of their APIs, and protect against malicious attacks and data breaches.
Securing APIs (Application Programming Interfaces) is crucial to protect sensitive data, prevent unauthorized access, and ensure the integrity of your systems.