Certo

69% of Browsers Worldwide Vulnerable: How Chrome Sync Enables Stealth Surveillance Without Malware

Google Chrome's standard synchronization feature can be silently abused to turn any browser into a surveillance tool, requiring only brief physical access to a victim's device and the addition of an attacker's Google account. Security researchers at Certo highlighted the technique after multiple cases involving intimate partner surveillance, including one incident where a woman’s visits to a family lawyer and domestic abuse support sites were monitored in real time by her partner. Once sync is enabled, browsing history, bookmarks, open tabs, autofill data, and saved passwords are automatically transmitted to the attacker’s profile, which can be viewed from any device worldwide without needing the victim’s password or installing spyware. Chrome provides no prominent warnings about new profiles or active synchronization, and alerts about logins are sent only to the account owner rather than the device owner. With Chrome holding a 69.65% global market share according to StatCounter data from June 2026, the method potentially affects millions of users on Android, iOS, Windows, and macOS. Experts recommend regularly checking connected profiles in browser settings, using Incognito mode for sensitive activity, securing devices with strong passcodes and biometrics, and immediately removing unknown accounts while changing important passwords.