CWE-204 (响应差异性信息暴露) — Vulnerability Class 189

CWE-204, Observable Response Discrepancy, is a design weakness where software systems provide inconsistent or distinct feedback based on internal states, inadvertently leaking sensitive information to unauthorized external actors. Attackers typically exploit this by analyzing variations in response times, error messages, or status codes to infer the existence of specific users, valid input formats, or underlying system configurations. For instance, a login system might return a generic error for invalid usernames but a specific message for invalid passwords, allowing attackers to enumerate valid accounts. To mitigate this risk, developers must ensure uniform response behaviors regardless of the specific internal failure or state. This involves standardizing error messages, normalizing response times, and implementing consistent logging practices that do not expose granular details about the application’s internal logic or data validity to the end user.