Secure Browser Plugin for Data Leak Alerts

Abstract

Modern web browsers represent a critical attack surface for exfiltrating sensitive data from users, yet browser security tools typically target code-level security properties, leaving user-driven data disclosures largely unaddressed. SecureGuard is a Chrome Manifest V3 browser extension that provides context-aware, real-time protection from sensitive data leaks by analyzing submitted forms, clipboard content, keystrokes, pasted text, and autofilled fields with asynchronous content scripts and event-triggered service workers. We utilize pattern recognition and field-specific contextual validation to identify sensitive data disclosure opportunities and scope resolution based on form fields, structure, and domain reputation to prevent their exfiltration. All analysis is done locally within the browser context to avoid exposing users' data. Our experimental evaluation attained 95% coverage of sensitive-data categories with an 8% false-positive rate across the tested set. The implementation added less than 2 ms of overhead on monitored events and decreased memory consumption by 30% compared to the persistent background page approach. In the user study, 78% of the users complied with the suggested action after a security warning, demonstrating the effectiveness of the UI feedback in prompting human agency. We evaluate SecureGuard's contribution to the growing literature on browser data-leak prevention tools by demonstrating its ability to offer comprehensive, privacy-preserving protection with minimal performance overhead while still providing opportunities for human agency in the process.