Webmail Security Hardening

Webmail security encompasses the defensive measures required to protect browser-based email clients from exploitation. Unlike desktop email applications, webmail runs entirely in the browser, making it vulnerable to client-side attacks like XSS, CSRF, and session hijacking. Effective webmail hardening includes Content Security Policy implementation, server-side file sanitization, SVG rasterization, session token rotation, and strict input validation on all user-supplied content including attachments. Organizations must balance security controls with usability while recognizing that webmail compromise grants attackers access to password resets, two-factor codes, and institutional communications critical for lateral movement.