Secfense User Access Security Broker (UASB) is a reverse proxy-based security layer that enables organizations to add strong multi-factor authentication (MFA) to any web application without modifying the application's source code. The broker operates by learning traffic patterns once deployed, allowing it to intercept and enforce authentication policies across all web applications in an organization. It supports any MFA method available on the market, including FIDO/passkeys, and can be deployed within minutes rather than weeks or months. UASB offers two operating modes: - Standard Mode: Users can reach the application and are prompted to authenticate after the login step. - Full Site Protection Mode: Access to the application is restricted entirely to users who have already verified their identity with a second factor inside a trusted network. Unauthorized users, bots, and external visitors cannot load the page at all. This Full Site Protection mode is positioned as an alternative to VPNs for securing corporate applications accessed remotely by employees. The solution is vendor-neutral and does not require developers, contractors, or third-party code to deploy. It is designed to protect legacy and modern web applications alike, covering all access points — not just login pages — and can enforce user access policies organization-wide across all employee accounts.