The Masks We (Think We) Wear: Privacy Threats of Browser-Extension Wallets in the Web3 Ecosystem

2026-07-07

AI Summary

Browser extension wallets, due to their deep integration with web pages, introduce significant privacy risks such as address linkage, cross-site tracking, and identity deanonymization. This work presents the first formal characterization of five privacy threats stemming from wallet behaviors and conducts a large-scale dynamic analysis of 85 popular Chrome extension wallets—collectively serving over 35 million users—employing RPC call monitoring, permission revocation testing, and cross-origin injection tracking to systematically uncover their privacy leakage mechanisms. The study reveals widespread deficiencies in permission management and vulnerabilities enabling cross-site tracking, which can lead to multi-address linkage, cross-session tracking, and the binding of on-chain assets with browsing activity. Based on these empirical findings, the paper proposes mitigations through refined implementation logic, strengthened industry standards, and stricter control over interface permissions.

Abstract

Cryptocurrency wallets are the primary interface for managing pseudonymous blockchain addresses, viewing balances, and interacting with Web3 applications. Although users typically assume that their addresses remain independent of each other unless intentionally revealed, modern wallets routinely communicate with both blockchain infrastructure and decentralized applications (dApps), generating network-side and web-side signals that may undermine this assumption. In this paper, we identify and formalize five privacy threats that arise directly from wallets interacting with the network and the web browser. Using large-scale dynamic measurements of 85 of the most popular Chrome Web Store browser-extension wallets (representing 35.16 million users), we observe that routine remote procedure call (RPC) operations leak structural links between a user's addresses; that the majority of Ethereum wallets implement permission revocation inconsistently and continue to expose previously revoked addresses across sessions; and that many wallets inject their provider interfaces into cross-origin iframes, enabling passive cross-site tracking beyond dApps and potentially real-world identity deanonymization without user interaction. Taken together, our results show that these wallet behaviors leak sensitive information that can be used to link multiple addresses to the same user, track wallet users across sessions and sites, and connect their browsing activity to their on-chain wealth. We discuss practical mitigations and show that many of these threats can be substantially reduced through improved wallet implementation, stronger privacy considerations in ecosystem standards, and stricter controls over provider exposure. Our results highlight the need for standardized, privacy-preserving wallet architectures.

Problem

• privacy threats
• browser-extension wallets
• Web3
• address linkage
• cross-site tracking

Innovation

• browser-extension wallets
• privacy threats
• address linkage
• cross-site tracking
• Web3 privacy