BRONZE SILHOUETTE

Bronze Silhouette, also known as Volt Typhoon, is a state-sponsored cyberespionage group believed to be operating on behalf of the People's Republic of China (PRC). Notorious for its sophisticated and aggressive cyber tactics, Bronze Silhouette has been implicated in compromising critical infrastructure organizations. The group has targeted U.S. government and defense organizations, with a particular focus on utilities, energy-sector companies, military bases, telecom companies, and industrial sites. Their modus operandi involves planting foothold malware, preparing for potentially disruptive and destructive attacks down the line. In May 2023, the National Security Agency (NSA), the Federal Bureau of Investigation (FBI), and the Cybersecurity Infrastructure Security Agency (CISA) issued a joint warning about Bronze Silhouette. This advisory was based on their incident response activities at compromised critical infrastructure organizations. The group uses small office/home office (SOHO) network devices to mask their activities, often running them off stolen or leased proxies, or via home or small office routers. Over a 37-day period, cybersecurity firm Secureworks observed Bronze Silhouette compromise nearly one-third of vulnerable Cisco routers. The threat from Bronze Silhouette continues to evolve and remains significant. The group has been linked to a zero-day exploit campaign against unpatched Versa Director systems. Black Lotus Labs attributed this campaign "with moderate confidence" to Bronze Silhouette and warned that these attacks are likely ongoing. Furthermore, officials have suggested that the group could use installed malware to trigger widespread disruptions, such as slowing any U.S. military response to a potential Chinese invasion of Taiwan. As such, it is imperative for organizations to heed warnings and take preventative actions against this persistent threat actor.