Chinese Group Uses BRICKSTORM Backdoor Against US Firms
⚠️ Google Threat Intelligence Group says a Chinese-aligned cluster has used the BRICKSTORM backdoor in intrusion campaigns since at least March 2025 against US legal and technology firms, SaaS providers and outsourcing companies. Attackers focused on harvesting emails and files from key individuals and establishing long-term footholds. The group, tracked as UNC5221, exploited zero-days, deployed BRICKSTORM on VMware appliances, and used credential theft and persistence mechanisms to evade detection. Google and partners have published detection guidance and a Mandiant scanner script to help identify infections.
