What Is API Security?

Learn about API security risks and best practices for protecting APIs against cyber threats

APIs (Application Programming Interfaces) have become the backbone of modern software development and business operations. They enable seamless integration between different systems and applications, powering everything from mobile apps to cloud services. However, with the increasing reliance on APIs comes a growing concern: API security.

Despite rigorous API security measures, the open nature of APIs makes them vulnerable to exploitation by malicious actors. This is where API gateways, API security best practices and the SEEBURGER BIS API Management capabilities become essential in building a resilient infrastructure for protecting APIs against ever-evolving security risks.

API security ensures that data exchanged via APIs is protected and that only authorized users and applications can interact with these interfaces. Five of the biggest reasons that API security matters include:

	Data protection APIs often transmit sensitive information, making them attractive targets for cyber criminals. An API security breach could expose customer data, financial information and proprietary business intelligence.
	Business continuity API security breaches can lead to service disruptions and damage a company's reputation, and downtime or data loss can result in financial losses and eroded customer trust.
	Compliance Many industries have strict regulations regarding data protection and privacy that require robust API security measures. Failing to comply can result in hefty fines and legal consequences.
	Innovation enablement Secure APIs allow businesses to safely expose their services and data, fostering innovation and partnerships. This can lead to new revenue streams and improved customer experiences.
	Competitive advantage Organizations with strong API security can move faster and with more confidence in the digital marketplace, gaining an edge over competitors who may be hesitant due to security concerns.

As the importance of APIs grows, so does the need to protect them from security risks. API security encompasses the practices and measures taken in protecting APIs from unauthorized access, data breaches and other cyber threats. Because APIs often handle sensitive data and provide access to critical systems, ensuring API security is paramount for any organization leveraging API technology.

While they promote innovation and efficiency, APIs also create potential entry points for cyber attacks. For example, high-profile API security breaches, such as the 2023 T-Mobile data breach involving 37 million accounts¹, underscore the risks associated with inadequate API security practices.

API security guarantees that data transmitted between systems is accurate. It ensures that data does not change while in transit and prevents tampering or illegal alteration. This is critical for ensuring the dependability and trustworthiness of API requests and answers.

The API security landscape is constantly evolving, with new threats emerging as technology advances. Understanding this landscape is necessary for developing effective API security strategies. Key challenges of this landscape include:

Increased attack surface

Each API endpoint represents a potential entry point for attackers, increasing the overall attack surface of an application.

Data exposure

Poorly designed APIs may inadvertently expose sensitive data, either through overly permissive access controls or by returning more data than necessary in responses.

Authentication and authorization

Ensuring that only authorized users and applications can access API resources is a complex task, especially in distributed systems.

Resource management and rate limiting

Without proper controls, APIs can be overwhelmed by too many requests, leading to denial of service.

Versioning and deprecation:

Managing multiple versions of APIs and securely deprecating old versions presents ongoing challenges.

Exposed to the public internet, public APIs require the most robust security measures as they face the broadest range of potential threats.

While more restricted, partner APIs still require strong security to protect against potential misuse by business partners.

Even though they're used within an organization, internal APIs still need protection to prevent insider threats and limit damage if other systems are compromised.

These APIs combine multiple data or service APIs and may inherit vulnerabilities from their components, requiring careful security design.

APIs play a central role in modernizing legacy systems and enabling new digital services as part of an organization’s digital transformation. This makes API security an important factor in the success of digital transformation initiatives.

Secure APIs allow organizations to:

Safely expose legacy system functionality to modern applications
Enable secure data sharing between different departments or with external partners
Support the development of new digital products and services
Facilitate the adoption of cloud and microservices architectures

Understanding potential threats is the first step in protecting APIs. According to the Open Web Application Security Project (OWASP), the following list comprises the top 10 API security risks in 2023²:

01	Broken object level authorization: This occurs when an API doesn't properly check that a user has the right permissions to access specific data or functionality. For example, a user might be able to access other users' data by manipulating API request parameters.
02	Broken authentication: Weak or improperly implemented authentication mechanisms can allow attackers to impersonate legitimate users. This could involve exploiting flaws in password reset functionality, session management, or JWT handling.
03	Broken object property level authorization: APIs sometimes return more data than necessary, potentially exposing sensitive information. This often happens when developers rely on the client-side to filter data, rather than limiting it at the API level.
04	Unrestricted resource consumption: Without proper controls, APIs can be overwhelmed by too many requests, leading to denial of service. This can be unintentional (e.g., a buggy client application) or a deliberate attack.
05	Broken function level authorization: Complex access control systems with multiple hierarchies and roles can lead to authorization flaws when administrative and regular functions aren't clearly separated. For example, attackers might exploit these issues to access administrative functions or other users' resources.
06	Unrestricted access to sensitive business flows: This occurs when APIs expose business processes without limiting their automated use. For example, a ticket-buying API might be vulnerable to automated purchasing that circumvents business rules, even if the code itself is bug-free.
07	Server-side request forgery: This vulnerability happens when APIs fetch remote resources without properly validating user-supplied URIs. An attacker could force the application to send malicious requests to internal systems, bypassing security measures like firewalls or VPNs.
08	Security misconfiguration: Modern APIs often have complex configuration options to increase customization. When engineers skip security best practices or miss certain configurations, these settings can create security vulnerabilities that attackers can exploit.
09	Improper inventory management: As APIs evolve, old versions may be left online without proper security updates, creating vulnerabilities. Lack of an API inventory can lead to "shadow APIs" that aren't properly secured.
10	Unsafe consumption of APIs: Developers often implement weaker security controls for data from third-party APIs compared to user input, treating it as more trustworthy. Attackers exploit this by targeting integrated third-party services to compromise the main API indirectly.

As API usage grows, so does the exposure to potential security vulnerabilities and attacks, making API security a critical component of any cyber security strategy.

In recent years, many high-profile API security breaches have highlighted the importance of strong API security measures. These incidents underscore the need for organizations to prioritize API security as part of their cyber security strategy.

Social media platform:
data exposure

In 2021, reports surfaced of a data exposure affecting 92% of LinkedIn’s users³. An alarming 700 million user profiles were compromised through an API vulnerability (i.e. an authentication-free API).

The breach allowed malicious actors to scrape sensitive information such as email addresses, phone numbers and inferred salaries. While LinkedIn insists this incident was not a breach but rather an aggregation of publicly accessible data, the implications are clear: inadequate authentication measures pose serious risks.

Telecommunications company:
data leak

A 2022 data breach at Optus, an Australian telecommunications company, was blamed in a 2024 court filing on a coding error that broke API access controls⁴. Optus experienced a data breach when an attacker exploited an unauthenticated API endpoint to access sensitive information from over 9 million people. The breach exposed personal data such as names, birth dates, addresses and passport numbers, which were later posted on a hacking forum after Optus declined to pay the hacker’s ransom.

As highlighted by these high-profile examples, the absence of strong authentication mechanisms can lead to extensive data exposure, putting millions of users at risk.

To effectively manage API security and prevent API security breaches, organizations need to be familiar with established industry standards and compliance frameworks.

API standardization is powering efficient industry networks, especially in the automotive industry. Standardization enables seamless B2B integration via APIs – an important factor for success that accelerates adoption, streamlines processes and drives innovation.

OAuth 2.0

Widely used framework for secure authorization.
Allows third-party applications to access user resources without exposing credentials.

OpenID Connect

Built on OAuth 2.0, adds an identity layer for authentication.
Allows clients to verify the identity of end users.

JSON Web Token (JWT)

Open standard for securely transmitting information between parties as a JSON object.
Often used for authentication and information exchange in web development.

Transport Layer Security (TLS)

Cryptographic protocol designed to provide communications security over a computer network.
Essential for securing data in transit for APIs.

OWASP API Security Top 10

Provides awareness about the most critical security risks to APIs.
Offers guidance on how to identify and mitigate these risks.

General Data Protection Regulation (GDPR)

Applies to organizations handling EU citizens' data.
Requires strong data protection measures and user consent for data processing.

California Consumer Privacy Act (CCPA)

Similar to GDPR but applies to businesses serving California residents.
Focuses on consumer rights regarding personal data.

Health Insurance Portability and Accountability Act (HIPAA)

Applies to healthcare organizations in the US.
Requires protection of sensitive patient health information.

Payment Card Industry Data Security Standard (PCI DSS)

Applies to organizations handling credit card information.
Mandates security controls for protecting cardholder data.

Implementing Standards and Ensuring Compliance

Regular audits:
Conduct periodic audits to ensure adherence to relevant standards and regulations.
Documentation:
Maintain detailed documentation of security practices and compliance efforts.

Employee training:
Ensure all employees are aware of and trained in relevant security standards and compliance requirements.
Third-party assessments:
Consider engaging third-party experts for independent security assessments and compliance validations.
Continuous monitoring:
Implement continuous monitoring solutions to ensure ongoing compliance and quick identification of potential violations.

An API gateway is an important part of an API solution’s security architecture. An API gateway acts as a reverse proxy to accept API calls, aggregate the services required to fulfill them and return the appropriate results.

An API gateway allows for centralized control over security policies by managing authentication and authorization and ensuring secure data transmission – all to help protect confidential company data.

Traffic Management

Controlling the flow of requests to prevent overload. This includes rate limiting, throttling, and load balancing.

Authentication and Authorization

Verifying the identity of API consumers and their access rights. This often involves integrating with identity providers and implementing OAuth 2.0 or other authentication protocols.

Request/Response Transformation

Modifying requests and responses to ensure compatibility and security. This can include data masking, protocol translation, and content validation.

Monitoring and Analytics

Providing insights into API usage and potential security issues. This helps in detecting anomalies and troubleshooting problems.

Caching

Storing frequently accessed data to reduce backend load and improve performance.

API Versioning

Managing different versions of APIs to ensure backward compatibility while allowing for updates and improvements.

Enhanced security

By centralizing security policies, API gateways reduce the attack surface and enforce authentication and authorization of API calls consistently, strengthening overall security.

Improved performance and scalability

Traffic management features ensure efficient resource utilization and accommodate increasing API traffic, which improve both performance and scalability.

Simplified API management

API gateways provide a single point of control for API management, simplifying tasks such as versioning, monitoring, and policy enforcement.

Compliance support

API gateways help organizations comply with industry standards and regulations by enforcing security policies, logging activities and providing audit trails to ensure adherence to compliance requirements.

Centralize API management

Use the gateway as a single point of entry for all API traffic, making it easier to apply consistent security policies.

Since APIs are vulnerable to a variety of attacks, including injection attacks, cross-site scripting (XSS), cross-site request forgery (CSRF) and denial-of-service (DoS), a proactive approach to API security best practices reinforces organizational resilience.

Recent high-profile API security breaches have revealed critical vulnerabilities, including insufficient authentication and authorization, poor incident response and insecure storage of API credentials. From these incidents, we can extract valuable lessons learned that highlight the need for API security best practices.

To protect APIs and maintain the integrity of digital ecosystems, consider implementing the following API security best practices:

01	Strong authentication mechanisms Use robust methods like OAuth 2.0 or JWT (JSON Web Tokens) to verify the identity of API consumers. Consider implementing multi-factor authentication for sensitive operations.
02	Input validation and output encoding Thoroughly validate and sanitize all input to prevent injection attacks. This includes checking data types, ranges, lengths and patterns. Output encoding converts data into a safe format for output, preventing malicious scripts from being executed.
03	Rate limiting Implement rate limiting and throttling to control the number of API requests a user can make within a specific timeframe. Protect APIs from abuse and overload, ensuring availability and performance for legitimate users.
04	Monitoring and logging Continuously monitor API traffic and maintain detailed logs for auditing and threat detection. Implement real-time alerting for suspicious activities.
05	Regular security audits Conduct periodic security assessments to identify and address vulnerabilities. Perform both automated scanning and manual penetration testing.
06	API versioning Implement API versioning to manage changes and updates without breaking existing integrations. Establish a clear deprecation policy for older API versions.
07	Principle of least privilege Ensure that API consumers are granted only the minimum level of access required for their needs. Regularly review and update access permissions.
08	Use HTTPS Encrypt all API traffic using HTTPS to protect data in transit. Ensure proper certificate management and consider implementing HSTS (HTTP Strict Transport Security).
09	Error handling Implement proper error handling that doesn't reveal sensitive information about APIs or backend systems. Avoid detailed error messages that could provide attackers with valuable information about the system architecture or security mechanisms.
10	API documentation and education Maintain comprehensive and up-to-date API documentation. Documentation and training help developers use APIs correctly and securely.
11	Data encryption Enforce TLS/SSL for data in transit. Enable data at rest encryption with strong algorithms like AES-256. Support API payload encryption for sensitive data.
12	Authorization strategies Implement Role-Based Access Control (RBAC) and Attribute-Based Access Control (ABAC) for fine-grained access control. RBAC simplifies permission management based on user roles. ABAC offers more granular control and allows real-time access decisions based on attributes like user role, location and time.

By implementing these API security best practices, organizations can strengthen their API security posture and protect APIs against a wide range of potential threats.

API management is a strategic approach to protecting APIs from threats and vulnerabilities throughout their lifecycle. It involves implementing governance measures, enforcing security policies and adapting to evolving risks to ensure the integrity, confidentiality and real-time availability of data.

API management platforms provide a comprehensive solution for securing, monitoring and optimizing APIs. By implementing a robust API management solution, organizations can ensure that their APIs are not only secure but also scalable, performant and easy to use.

Choosing an API management platform

An API management platform is an integration platform with API management and API integration capabilities that provides a centralized resource for supporting real-time integrations between applications, people and processes.

Integration platforms connect diverse systems and applications, and generally, they provide a suite of capabilities and services that safeguard data throughout an API’s lifecycle. At its core, an integration platform acts as a secure gateway, implementing authentication and authorization mechanisms such as OAuth 2.0 and multi-factor authentication to ensure that only verified users and applications can access protected resources. By enforcing encryption protocols for data in transit and at rest, the platform creates a secure channel for API communications, protecting sensitive information from interception and unauthorized access.

An integration platform also provides advanced threat protection capabilities, including Web Application Firewall (WAF) functionalities and DoS mitigation strategies. These features work in tandem with real-time monitoring and analytics tools to detect and respond to potential security threats. And most importantly, an integration platform's ability to manage the entire API lifecycle – from development and testing to deployment – ensures that API security best practices are embedded in every stage. This holistic approach facilitates API-led B2B integration, improving overall API security while simplifying compliance with industry regulations and standards.

Key features of an API management platform include

The right platform offers IT teams the capabilities they need to build and maintain a secure and scalable ecosystem. Here’s a list of eight ways that an integration platform like the SEEBURGER BIS Platform ensures API security:

Centralized control for authentication and authorization mechanisms

Implements OAuth 2.0 and OpenID Connect protocols
Supports multi-factor authentication (MFA)
Provides fine-grained access control with role-based policies

Encryption

Enforces TLS/SSL for data in transit
Enables data at rest encryption with AES-256
Supports API payload encryption

API gateway functionality

Acts as a reverse proxy to abstract backend services
Offers request/response transformation and validation
Enables API versioning and deprecation management

Monitoring and analytics

Provides real-time monitoring of API traffic and performance
Offers advanced analytics for anomaly detection
Supports integration with SIEM solutions for centralized logging

Compliance support

Ensures adherence to industry standards (e.g., PCI-DSS, HIPAA)
Provides audit trails and activity logs for compliance reporting
Offers policy enforcement for data residency and sovereignty

API full lifecycle management

Streamlines API development, testing and deployment processes
Enables secure API documentation and discovery
Provides sandboxing for secure API testing

Scalability and performance

Ability to handle high volumes of API traffic
Caching mechanisms for improved performance

Developer tools and documentation

Comprehensive API documentation
Developer portals for easy API discovery and integration

By combining these capabilities, the SEEBURGER BIS Platform provides a holistic approach to security that helps organizations to operate APIs in a secure, scalable and efficient manner. It not only protects against security risks, but also facilitates compliance with regulatory requirements and improves the performance of mission-critical API-based applications.

In conclusion, APIs are integral to enabling seamless communication and real-time functionality across multiple applications and services. As the use of APIs continues to expand, understanding API gateways, API security best practices and implementing an API management platform are an organization’s means for protecting APIs and their sensitive data.

The SEEBURGER BIS Platform API Management and API Integration capabilities empowers IT teams to manage APIs and support real-time integrations between applications, people and processes.

Case Study

For example, HARTMANN, a leading European provider of medical and healthcare solutions, relies on the SEEBURGER BIS Platform for API management and API integration to expand its outpatient business with seamless connectivity of its digital products. “The SEEBURGER BIS Platform optimally supports the real-time requirements of the digital healthcare market, such as online availability queries in the pharmacy network” says the Director of Digital Product Engineering at HARTMANN.

Read the case study to learn more