What analysis can help find vulnerabilities in web applications while they are running?

Dynamic Analysis is the correct choice for finding vulnerabilities in web applications while they are running. This method involves testing the application in a real or simulated environment to identify potential security flaws that may be present during operation. By analyzing the application's behavior in real-time, dynamic analysis can reveal issues related to how the application manages user inputs, interacts with the database, and responds to various attack vectors.

This type of analysis contrasts with Static Application Security Testing, which evaluates the application’s code and design without executing it. While static testing is crucial for identifying vulnerabilities early in the development process, it does not account for how the application behaves under real-world conditions. Therefore, it will miss issues that only become apparent during runtime, such as session management weaknesses or authorization bypass vulnerabilities.

Secure Design Patterns, while important for creating robust application architecture, do not directly identify vulnerabilities in running applications. Similarly, Container APIs are related to managing containerized applications and do not specifically address security vulnerability analysis within web apps. Thus, dynamic analysis is essential for uncovering runtime vulnerabilities and ensuring that web applications remain secure during operation.