A Chinese-nexus advanced persistent threat actor, UAT-9686, is actively targeting Cisco AsyncOS Software for Secure Email Gateway and Secure Email and Web Manager. The campaign, ongoing since late November 2025, exploits non-standard configurations to execute system-level commands and deploy a persistent Python-based backdoor called AquaShell. Additional tools observed include AquaTunnel for reverse SSH tunneling, chisel for TCP/UDP tunneling, and AquaPurge for log clearing. The attackers can execute encoded commands in the system shell and create reverse connections to attacker-controlled servers. This sophisticated attack aligns with tactics used by other Chinese APT groups, raising concerns about potential widespread impact on email security infrastructure.
