China-Linked UNC3569 Exploited Sogou Input Method Flaw to Deploy GRAYRABBIT Backdoor
Sep 11, 2026
Vulnerability / Browser Security
A China-linked hacking group exploited a flaw in Sogou Input Method , one of the most widely used tools for typing Chinese characters on Windows, to install a backdoor on victims' computers, security company Gen Digital said in research published Thursday . The attack started with a crafted link and ended with the attacker able to do anything the logged-in user could do. Tencent, which owns and develops Sogou, fixed the flaw in April 2026. Gen found the flaw while investigating a live intrusion by UNC3569 , a group that Google Threat Intelligence ties to China and places in the country's hacker-for-hire scene. Google has tracked the group since 2021 and says it has targeted government, education, technology, and finance sectors, mostly in East and Southeast Asia. The backdoor it installed is GRAYRABBIT , a small program the group has used for years and that Google describes as its first step onto a machine. It gives an attacker a remote command shell, allows fil...