alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Librarian Ghouls Domain (hostingforme .nl in TLS SNI)"; flow:established,to_server; tls.sni; dotprefix; content:".hostingforme.nl"; endswith; fast_pattern; reference:url,www.kaspersky.ru/blog/librarian-ghouls-cad-formats/38199/; classtype:trojan-activity; sid:2055807; rev:1; metadata:attack_target Client_Endpoint, created_at 2024_09_09, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_09_09, reviewed_at 2025_04_15, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)