alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE [401TRG] Malicious SSL Cert (Dreambot CnC)"; flow:from_server,established; tls.cert_subject; content:"CN=giltipolsfols.xyz"; nocase; fast_pattern; endswith; tls.cert_issuer; content:"C=US, O=Let|27|s Encrypt, CN=Let|27|s Encrypt Authority X3"; reference:md5,74487b631e5688ad6affdd23340563bd; reference:url,twitter.com/w3ndige/status/1199375393297448961; classtype:domain-c2; sid:2029134; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2019_12_12, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_24, mitre_tactic_id TA0042, mitre_tactic_name Resource_Development, mitre_technique_id T1587, mitre_technique_name Develop_Capabilities;)