Proactively Reduce API Risks with Upwind’s API Vulnerability Testing

APIs are the foundation of modern software. From mobile apps to cloud-native platforms, they allow services to communicate, scale, and deliver value quickly. In fact, more than 70% of all internet traffic flows through APIs today, which makes them both essential and high-risk. But as APIs have become more critical, they’ve also become one of the most targeted attack surfaces in cloud environments.

At Upwind, we’ve built API Vulnerability Testing that reflects how APIs are actually deployed and used today. Upwind continuously tests APIs in real time based on how they behave in the wild instead of relying on typically outdated documentation on how they’re expected to behave. It’s a modern approach to securing a modern problem.

The Rapid Increase of API Vulnerabilities

While we noted this above, it bears repeating, APIs now account for the majority of internet traffic. As organizations continue adopting microservices, automation, and third-party integrations, that number – and the associated risk exposure and complexity – keeps growing. In many organizations, APIs are released faster than they can be documented or reviewed. Teams ship features at the speed of CI/CD, often creating endpoints security never sees. This drift between staging and production is common, and sensitive data such as personal health information can unknowingly flow through unprotected routes.

Meanwhile, attackers are adapting. They’re no longer just targeting web apps or infrastructure; they are instead going straight for APIs, looking for misconfigurations, broken access controls, and business logic flaws that are harder to detect and easier to exploit. The result is a growing set of vulnerabilities most traditional tools aren’t equipped to catch.

According to Gartner, by 2025, more than 50% of data theft will be due to unsecure APIs. Venturebeat states that API vulnerabilities are costing businesses $75 billion annually.

The Runtime Advantage

Traditional API security tools often fall into two camps: testing APIs before deployment using specs and code, or analyzing traffic at the edge through API gateways and WAFs. These approaches can be useful, but they miss critical blind spots. Pre-deployment tools can’t detect what hasn’t been defined. If an endpoint is undocumented or created outside the spec (e.g.  due to CI/CD automation, hotfixes, or incomplete documentation) it’s invisible. Perimeter defenses, on the other hand, often fail to see internal-only APIs or detect deeper behavioral issues like broken access controls or flawed business logic.

“Upwind’s testing for API vulnerabilities has been instrumental in our API security practice. We’ve been able to proactively identify exposed endpoints and data flows, providing us with increased visibility in to our API landscape. Upwind’s runtime-centric approach to securing APIs has helped us prioritize real risks and reduce our attack surface without slowing down development.”

-Sameer Sule, CISO & VP, Compliance, Rhapsody

Runtime testing closes these gaps. It captures the full picture, whether or not an API is documented or intended to be exposed. By observing APIs exactly as they operate in production, runtime testing surfaces vulnerabilities that only appear under real-world conditions.

Upwind’s runtime-first model gives teams immediate, actionable insights. It prioritizes risk based on actual usage, exposure, and data sensitivity, allowing them to focus on what’s exploitable, not just what’s theoretically severe.

Real-Time API Testing in the Upwind Platform

Upwind brings the runtime model to life by continuously testing APIs as they run in production. We don’t rely on static definitions, synthetic traffic, or staging environments. Instead, we use lightweight eBPF-based sensors to passively observe live API behavior inside your infrastructure.

This means we see exactly how endpoints are used, including:

• the requests they handle
• the parameters they accept
• the authentication they may require
• and how they respond under real workloads

This deep runtime context allows us to identify vulnerabilities like broken authentication, improper authorization, and sensitive data exposure with precision. And because testing is passive and ongoing, it doesn’t disrupt production or require developers to slow down.

With Upwind, security becomes part of the live environment. Unlike traditional scan-time tools that only capture a snapshot, Upwind observes APIs continuously, making it possible to detect issues that emerge under real traffic conditions. It’s always on, always current. 

Here’s what that looks like:

• Live Behavior-Based Testing: Upwind observes real API traffic and assesses endpoints based on how they behave in production, detecting logic flaws, misconfigurations, and missing access controls.
• OWASP API Top 10 Coverage: Upwind continuously tests for common and critical issues, including broken authentication, injection vulnerabilities, mass assignment, and excessive data exposure.
• Runtime-Aware Execution: The Upwind Platform understands how your APIs are used, including authentication flows, session handling, and response behavior. This context allows for precise, relevant testing.
• Exploitability-Based Prioritization: We factor in external exposure, frequency of use, and presence of sensitive data to rank vulnerabilities by actual risk—not just by category.
• Safe, Passive Testing: No simulated attacks or test payloads. We rely entirely on observed traffic, ensuring stability in production environments.

Moving Beyond Detection: Proactive API Risk Reduction

As APIs grow more dynamic and deeply integrated into business logic, the need to go beyond detection becomes critical. That’s why we are continuing to expand our capabilities into Cloud-Native Application Detection and Response (CADR), giving organizations the power not just to find vulnerabilities, but to reduce their attack surface proactively and respond in real time.

This means:

• Identifying exposed or shadow APIs before they can be abused
• Correlating runtime behavior with cloud infrastructure context to reveal meaningful attack paths
• Automatically hardening misconfigured or risky endpoints, even before a vulnerability is exploited
• Responding in real-time to suspicious API behavior that may indicate abuse, misuse, or exfiltration

These capabilities shift API security from reactive to proactive. Upwind doesn’t just tell you what’s wrong. We help you minimize your attack surface. For example, we can identify an exposed internal API accepting unauthenticated traffic so your team can shut it down before it’s exploited. We also help close gaps before attackers can take advantage of them.

Final Thoughts

APIs are now central to modern applications. They are also one of the most vulnerable components. . Most security tools can’t keep up with how quickly APIs change and how widely they are deployed. Upwind’s API Vulnerability Testing is built for this pace. By analyzing APIs in runtime, we help teams detect, prioritize and reduce real risk based on how APIs actually behave. With the addition of CADR, we go beyond detection to help organizations actively reduce their attack surface. .

See how Upwind secures APIs where they run. Schedule a demo with us and experience  continuous, context-aware API security in action.