alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed DonotGroup Related Domain (letentinfo .info in TLS SNI)"; flow:established,to_server; tls.sni; bsize:15; content:"letentinfo.info"; fast_pattern; reference:md5,3d98b4c649408c7021b1e01dc72f2ae4; reference:url,twitter.com/ginkgo_g/status/1777256849030709560; classtype:domain-c2; sid:2052101; rev:1; metadata:attack_target Client_Endpoint, created_at 2024_04_16, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_16, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)