alert ssh any any -> $HOME_NET any (msg:"ET MALWARE Nosviak C2 SSH Server Banner"; flow:established,to_client; content:"SSH-2.0-OpenSSH_8.6p1 "; fast_pattern; pcre:"/^Nosviak[^\x40]*\x40v(?:\d+\x2e){1,2}\d+/R"; reference:url,censys.com/pivoting-for-nosviak/; classtype:command-and-control; sid:2059675; rev:1; metadata:attack_target Client_Endpoint, created_at 2025_01_27, deployment Perimeter, confidence High, signature_severity Major, tag c2, updated_at 2025_01_27, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)