Security researchers at Guardio Labs have uncovered a significant security vulnerability in the Opera web browser, dubbed “CrossBarking,” which potentially exposed users’ sensitive data to malicious browser extensions. The vulnerability allowed unauthorized access to private browser APIs, potentially compromising critical features including cryptocurrency wallets, VPN services, and other sensitive components.
Technical Analysis of the CrossBarking Vulnerability
The vulnerability’s core issue stems from Opera’s privileged domain architecture, where several publicly accessible domains – both Opera-owned and third-party – maintained privileged access to internal browser APIs. These domains included crypto-corner.op-test.net and opera.atlassian.net. Malicious actors could exploit this setup by injecting harmful JavaScript code through browser extension content scripts into these privileged domains, effectively bypassing intended security boundaries.
Security Impact and Attack Vector Analysis
The exploitation of CrossBarking could enable attackers to perform several high-impact operations, including:
- Capturing screenshots of users’ active browser tabs
- Intercepting session cookies leading to account compromises
- Manipulating DNS-over-HTTPS settings to facilitate phishing attacks
- Gaining unauthorized access to users’ cryptocurrency wallets
Proof of Concept and Distribution Method
To demonstrate the vulnerability’s severity, security researchers developed a proof-of-concept extension and successfully published it on the Chrome Web Store. It’s crucial to note that this vulnerability was specific to Opera and did not affect other Chromium-based browsers. The attack vector required users to install a malicious extension, which could be disguised as legitimate software.
Mitigation and Security Response
Opera’s security team addressed the vulnerability promptly in September 2024 following Guardio Labs’ responsible disclosure. The company emphasized that no instances of CrossBarking exploitation were detected in the wild, though the potential impact warranted immediate attention and remediation.
This incident underscores the critical importance of robust browser extension security measures. Security experts recommend implementing enhanced verification procedures for browser extensions, including thorough developer identity verification and continuous monitoring of installed add-ons. Users should exclusively install extensions from the official Opera Add-ons Store, which implements stringent manual review processes. Additionally, regular security audits of browser components and privileged domains should be conducted to prevent similar vulnerabilities in the future.
