Chinese Backdoor Grants Year-Long Access to US Firms
🔐 Chinese state-linked actors deployed a custom Linux/BSD backdoor called BRICKSTORM on network edge appliances to maintain persistent access into U.S. legal, technology, SaaS and outsourcing firms. These implants averaged 393 days of undetected dwell time and were used to pivot to VMware vCenter/ESXi hosts, Windows systems, and Microsoft 365 mailboxes. Mandiant and Google TAG attribute the activity to UNC5221 and have released a scanner and hunting guidance to locate affected appliances.
