code class$=$"asciimath"$>$ Insecure design refers to fundamental weaknesses in application design, which may not be addressed even if the implementation is flawless. It encompasses missing or ineffective security controls that fail to protect against specific attacks. There is a distinct difference between insecure design, which indicates a lack of security considerations during the design phase, and insecure implementation, which may involve mistakes made during coding. Security misconfiguration occurs when applications are not properly secured across any layer of their stack. Vulnerabilities may arise from inadequate security hardening, unnecessary features that remain enabled, or the presence of default accounts and unchanged credentials. Additionally, informative error messages that disclose stack traces can pose security risks by revealing insights into the application's inner workings. Applications can be vulnerable if the versions of the components they utilize $($both client$-$side and server$-$side$)$ are unknown, outdated, or unsupported. This also includes the underlying operating system, database management systems $($DBMS$),$ libraries, and runtime environments. Regular vulnerability scanning and active monitoring of components for updates are crucial to maintaining security. Robust identification and authentication mechanisms are essential to prevent unauthorized access. Vulnerabilities may occur if applications allow automated attacks $($e$.$g$.,$ credential stuffing$),$ permit brute force attacks, or use default, weak passwords that are easy to guess. Proper session management and strong password policies are key controls to mitigate these risks.