CWE-521 (弱口令要求) — Vulnerability Class 119

CWE-521 represents a critical authentication weakness where software fails to enforce robust password policies, allowing users to select trivially guessable credentials. Attackers typically exploit this vulnerability through offline brute-force or dictionary attacks, rapidly compromising accounts by testing common words, simple patterns, or previously leaked password databases against the weak hashes. Because the system permits low-entropy secrets, the computational effort required to breach accounts is significantly reduced, facilitating unauthorized access and potential data exfiltration. To mitigate this risk, developers must implement strict validation mechanisms that mandate minimum length, complexity, and uniqueness requirements. By integrating real-time feedback and checking against known compromised password lists during registration, organizations can ensure users create strong, resilient passwords that withstand automated cracking attempts and protect sensitive system resources.