API security is a form of cybersecurity that covers the protocols, processes, and best practices for securing application programming interfaces (APIs) against data breaches, unauthorised access, and other threats.
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API security combines a wide range of tools to help organisations shield application programming interfaces (APIs) from being compromised. It safeguards sensitive and confidential information and secures web and mobile applications, cloud services, and Internet of Things (IoT) devices.
What is an API?
Application programming interfaces (APIs) are the code-based rules and protocols that let different software applications interact, communicate with each other, and share data.
Since APIs ‘talk’ to different apps and exchange data between them, they can also be a way for bad actors to gain access to applications, the systems they run on, and the data they carry.
How does API security work?
API security uses tools like authentication and authorisation, proactive access controls, data encryption technologies, and threat detection and response measures to defend APIs against a variety of accidental and malicious threats, including:
- Data breaches
- Data theft or misuse
- Distributed denial-of-service (DDoS) attacks
- Hacks and other unauthorised access attempts
- Vulnerability exploits
- Injection attacks
- Authentication-based attacks for account takeover
- Broken access control attacks
- Man-in-the-middle (MITM) attacks
What are the main protocols of APIs?
APIs come in all shapes and sizes. Some common ones include:
- REST (representational state transfer) APIs—let apps share data and other resources through HTTP (hypertext transfer protocol) requests using web API architecture principles. A majority of APIs are based on REST today.
- SOAP (simple object access protocol) APIs—enable endpoints to send, receive, and share data securely based on XML messages. Enterprise applications, such as payment processing, often rely on SOAP because of more strict communication standards.
- GraphQL APIs—provide faster and precise retrieval of data through on-demand queries, which makes this protocol suitable for applications that require a huge amount of data queries, such as e-commerce applications where large volumes of product, user, and order data are transacted.
- RPC (remote procedure call) APIs—allow a program to execute on a remote server as if it were a local machine. While REST or gRPC (modern implementation of RPC) are replacing RPC in some use cases. RPC is ideal for complex calculation on a different server, such as executing AI algorithm to identify fraud on remote servers.
APIs basically include any programming interface that lets software developers access and integrate data or functions from different applications into their own apps.
The advantage of APIs is that developers don’t have to create all their own functionality from scratch. Instead, they can simply ‘borrow’ from existing applications to make their own software better.
Why is API security important?
API security is important because it helps organisations protect the integrity of their APIs, keep sensitive or confidential information out of the hands of cybercriminals, and safeguard their reputations and the trust of their partners and customers.
This matters because organisations are increasingly depending on APIs to deliver products, services, and information safely and securely across multiple different platforms and devices. This includes mobile apps, cloud-native and cloud-based applications, web applications, and software as a service (SaaS) apps.
The data those applications use has become a valuable asset and an essential part of doing business. APIs are the front door and the communication channels for the data in these applications. If compromised, it could have serious consequences for productivity, profitability, and brand status—up to and including significant financial penalties, lengthy business disruptions, and even legal ramifications.
Because of these factors, APIs have become a primary attack vector for attackers.
A robust API security solution also helps organisations stay compliant with all government and industry laws and regulations surrounding data privacy, including the General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA).
What are the top API security risks?
As the use of APIs grows more widespread, the number, frequency, and sophistication of cyberattacks and other risks to API security are also on the rise. Some of the biggest and most dangerous risks to API security include:
- Broken authentication and authorisation—where cybercriminals can access APIs without proper authentication, that allows them to access functions or confidential data that they are not supposed to. They could also steal credentials, API keys, or API tokens to execute an account takeover.
- Misconfiguration—where bad actors take advantage of flaws to attack your APIs. For example, they can initiate denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks against APIs that lack adequate rate limiting.
- Encryption issues—bad actors try to intercept unencrypted API communications.
- Shadow and zombie APIs—with API sprawl where developers create many APIs, there can be forgotten legacy APIs that are publicly available but not monitored. These APIs lack security measures and become an easy target for attackers.
- Abnormal API requests—there is a clue on API attacks even though attackers pretend to be harmless. This includes SQL injection and command injection attacks.
As attacks on APIs become more prevalent, businesses of all sizes are at risk. Some of the largest and most secure companies in the world have had their APIs compromised in just the last few years alone, including Honda, Dell, and T-Mobile.
In 2024, vulnerability exploit attacks also compromised the private accounts of hundreds of millions of users of services like LinkedIn, Facebook, Snapchat, Duolingo, and X (formerly Twitter).
OWASP's top 10 API security risks
In 2023, the Open Web Application Security Project (OWASP) published an updated list of the Top 10 API Security Risks to help businesses identify, understand, and protect themselves from the most dangerous threats to API security. The list includes:
- Broken object-level authorisations, which expose the endpoints that handle object identifiers.
- Broken authentication mechanisms that let bad actors steal authorisation tokens or assume other users’ identities.
- Broken object property level authorisations resulting from improper or inadequate validations at the object property level.
- Unrestricted resource consumption of network bandwidth, memory, storage, CPUs, or other resources through distributed denial-of-service (DDoS) and other attacks.
- Broken function level authorisations, which create access and authorisation flaws that can be exploited by cybercriminals.
- Unrestricted access to sensitive business flows arising from the automated exploitation of APIs used to carry out business functions, such as making online purchases or posting comments to social media.
- Server-side request forgery (SSRF) flaws that let attackers bypass firewalls and virtual private networks (VPNs) to compromise APIs that fetch remote resources.
- Security misconfigurations that leave APIs and their support systems vulnerable to malicious breaches or attacks.
- Improper inventory management that can expose endpoints in APIs.
- Unsafe consumption of APIs that allow bad actors to infiltrate APIs by targeting third-party data or services.
What tools are used in API security?
API solutions combine a number of different tools, technologies, and best practices to safeguard APIs at every stage of their lifecycle, from design and coding to implementation and maintenance. This includes:
- API gateways that help secure, manage, and control the flow of data
- Encryption protocols to protect against data theft, breaches, or misuse
- API keys or tokens to manage access authorisations
- Transport layer security (TLS) to safeguard data while it’s in transit
- Application firewalls to secure APIs, authorisation credentials, and sensitive information
Examples of API security best practices
There are several best practices every organisation should follow when creating an API security strategy to protect data and applications from both known and emerging threats.
First, organisations should inventory all their existing APIs to find and fix any weak points, flaws, or vulnerabilities in their security.
A series of rigorous authentication and authorisation mechanisms should also be implemented and enforced to monitor and control who has access to APIs and the data they contain, including tools like open authorisation (OAuth) tokens, OpenID Connect (OIDC) controls, API keys, and/or mutual TLS (mTLS).
Advanced encryption measures should be set up to protect data from being stolen, used, or accessed without authorisation. In addition, rate limiting, throttling measures, and data quotas can all be employed to help prevent the abuse, overuse, or exploitation of APIs, preserve bandwidth, protect API backends, and mitigate the risk of APIs being overwhelmed by DDoS or other attacks.
Lastly, all API security systems, tools, and endpoints should be regularly tested and continuously monitored to scan for vulnerabilities, identify any potential flaws or misconfigurations, and make sure API security defences stay comprehensive and up to date.
What’s next in API security?
New threats, attack vectors, and security risks will continue to emerge as API technology evolves. This is increasing important as enterprises adapt more and more agentic AI communications through MCP (Model Context Protocol) which runs on APIs. To address these challenges, API security will likely come to rely more heavily on artificial intelligence (AI) technologies such as neural networks and machine learning.
These new AI-driven tools will help organisations improve API security threat detection and response capabilities, bolster defences against data breaches and cyberattacks, and predict and prevent most threats before they cause lasting damage.
Other future API security trends will likely include a growing need for continuous API security assessments, application of industry standards and best practices, and compliance with applicable data privacy regulations. Practices like these will help organisations safeguard valuable information and maintain the integrity, security, and resilience of their APIs.
Where can I get help with API security?
Trend Vision One™ Cloud Security offers comprehensive, industry-leading protection against cyber threats, cyberattacks, and other risks for cloud and hybrid cloud environments.
Combining real-time visibility and security, continuous monitoring and assessment, and seamless integration with existing security and cybersecurity tools and technologies, Cloud Security provides complete worry-free protection of your entire attack surface, including cloud containers, workloads, cloud assets, and application programming interfaces (APIs).
Frequently Asked Questions (FAQ's)
What does API mean?
API stands for “application programming interface”. APIs are the backend frameworks that let mobile and web applications interact, share data, and communicate with each other.
Why do I need API security?
API security helps organisations protect APIs from cyberattacks and safeguard sensitive, confidential, and proprietary data from being compromised or stolen.
Can you give me an example of an API?
APIs we use every day include payment processing APIs that let you use PayPal to pay for online purchases, Google Maps APIs that let you track deliveries or find an Uber, and login APIs that let you log in to websites using your Facebook or Google account.
How does API security work?
API security prevents data breaches and cyberattacks by limiting access to APIs and keeping API data from being accessed without authorisation.
How do you secure an API with https?
Web APIs use HTTP to share data. Enabling HTTPS can encrypt shared data and secure communications between representational state transfer (REST) APIs and HTTP clients.
What are the best ways to secure an API?
APIs can be secured using a variety of tools including rate limiting, data throttling, authorisation and access controls, schema validation, and DDoS mitigation.
What’s the difference between API authentication and authorisation?
API authentication verifies the identity of API users. API authorisation controls which data or services they can access.
How does OAuth 2.0 help in API security?
OAuth 2.0 is an industry-standard authorisation protocol that dictates, limits, or manages how third-party clients access APIs.
How do API gateways improve API security?
API gateways secure API traffic by authenticating and controlling access to data as it flows between APIs and clients or users.
How can I secure my API endpoints?
API endpoints can be secured using tools like API gateways, API tokens, OAuth authentication, zero-trust policies, and mutual TLS (mTLS) encryption.