alert dns $HOME_NET any -> any any (msg:"ET MALWARE APT DarkHydrus DNS Lookup 21"; dns.query; content:"phicdn.world"; nocase; endswith; classtype:targeted-activity; sid:2026795; rev:3; metadata:attack_target Client_Endpoint, created_at 2019_01_11, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag APT, tag DNS_tunneling, tag DarkHydrus, updated_at 2020_09_16;)