alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (Gozi ISFB)"; flow:established,to_server; tls.sni; content:"basa.nutarborg.com"; bsize:18; reference:md5,f461bf12c4d3ed1d25af638d9f21ca0f; reference:url,twitter.com/JAMESWT_MHT/status/1250391330192269314; classtype:domain-c2; sid:2030030; rev:1; metadata:attack_target Client_and_Server, created_at 2020_04_27, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_04_27, mitre_tactic_id TA0042, mitre_tactic_name Resource_Development, mitre_technique_id T1587, mitre_technique_name Develop_Capabilities;)