Helldown Ransomware: an overview of this emerging threat

**Helldown** is a newly observed, active ransomware intrusion set that has targeted at least 31 victims by exploiting Zyxel firewall vulnerabilities to gain access; the report details Windows and Linux (ESX-focused) variants, double-extortion data theft and publication, TTPs observed during intrusions, and provides multiple IoCs and file hashes for detection and response.