alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed OtterCookie Domain (payloadrpc .com) in TLS SNI"; flow:established,to_server; tls.sni; bsize:14; content:"payloadrpc.com"; fast_pattern; reference:url,jp.security.ntt/tech_blog/contagious-interview-ottercookie; classtype:domain-c2; sid:2059025; rev:1; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2025_01_07, deployment Perimeter, malware_family OtterCookie, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_01_07, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)