Which vulnerability is unlikely to be detected by a web vulnerability scanner?

Race conditions are a type of vulnerability that arise from the timing of specific actions in a system that can lead to unexpected behaviors or security breaches. These vulnerabilities often occur in situations where multiple processes are executed concurrently and the outcome depends on the timing of their execution. They can be particularly challenging to identify because they depend on the specific conditions and timing of execution that may not be easily replicated in a typical testing environment.

Web vulnerability scanners are primarily designed to identify common issues associated with web application security, such as input validation flaws or misconfigurations that can lead to vulnerabilities like cross-site scripting or SQL injection. These scanners analyze how the web application responds to different inputs and requests to pinpoint certain security weaknesses. However, race conditions are often not triggered by simple input or requests, and they might require specific sequences of events or timing that a scanner cannot assess in the course of its automated tests.

This limitation means that while web vulnerability scanners can effectively highlight many known vulnerabilities, race conditions typically necessitate a more nuanced approach including manual testing, code reviews, or specialized testing techniques that simulate concurrent processes. This makes race conditions a category of vulnerabilities that scanners are unlikely to detect reliably.