The Emperor is Now Clothed: A Secure Governance Framework for Web User Authentication through Password Managers

TL;DR

This paper addresses the security and usability gaps in current web password-management paradigms by introducing Berytus, a browser-based governance framework that mediates interactions between web applications and secret managers. It defines two APIs to enable programmable, end-to-end encrypted sessions and implements a Firefox-based proof of concept to demonstrate registration, authentication, and authenticated key exchange between web apps and secret managers. Berytus provides certificate-based web app authentication, origin- and key-based credential mapping, and an application-level E2EE channel to mitigate XSS/ECI and TPitM attacks, surpassing existing approaches like HTML Autofill, Credential Management API, and ByPass in security coverage while preserving developer control over UX. Functionality-wise, it supports multi-step and multi-factor authentication, flexible account designs, and secret-manager extensibility, aiming to maintain conventional web usage patterns and ecosystem openness. The work lays groundwork for practical deployments and suggests future usability studies to refine integration and adoption.

Abstract

Existing approaches to facilitate the interaction between password managers and web applications fall short of providing adequate functionality and mitigation strategies against prominent attacks. HTML Autofill is not sufficiently expressive, Credential Management API does not support browser extension password managers, and other proposed solutions do not conform to established user mental models. In this paper, we propose Berytus, a browser-based governance framework that mediates the interaction between password managers and web applications. Two APIs are designed to support Berytus acting as an orchestrator between password managers and web applications. An implementation of the framework in Firefox is developed that fully supports registration and authentication processes. As an orchestrator, Berytus is able to authenticate web applications and facilitate authenticated key exchange between web applications and password managers, which as we show, can provide effective mitigation strategies against phishing, cross-site scripting, inline code injection (e.g., by a malicious browser extension), and TLS proxy in the middle attacks, whereas existing mitigation strategies such as Content Security Policy and credential tokenisation are only partially effective. The framework design also provides desirable functional properties such as support for multi-step, multi-factor, and custom authentication schemes. We provide a comprehensive security and functionality evaluation and discuss possible future directions.

Figures (5)

• Figure 1: Comparing HTML Autofill, Cred. Mgmt API, ByPass, and Berytus architecture
• Figure 2: Illustration of the Berytus communication model between the web application and the secret manager along with their components.
• Figure 3: (Simplified) sequence diagram showing the interactions between the web app, channel, operation and the secret manager during the Berytus login operation initiation process. The relayed user intent is either an authentication intent or registration intent.
• Figure 4: Berytus E2EE & its effectiveness against TPitM and monkey-patching attacks
• Figure 5: Left: Berytus secret manager selection prompt. Each listed secret manager displays the number of registered accounts associated with the web app. Right: Secret* login operation approval prompt when the user does not have any registered accounts. In both cases, domain-based credential mapping was used.