alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Dragonfly Backdoor.Goodor Go Implant CnC Beacon 1"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"."; content:"?"; distance:3; within:2; content:"="; distance:3; within:1; content:"&"; distance:32; within:1; pcre:"/\.(?:aspx|txt)\?[a-z0-9]{3}=[a-f0-9]{32}&[a-z0-9]{3}=[^&]+&[a-z0-9]{3}=[a-f0-9]{32}$/"; http.header; content:"Go-http-client/1.1|0d 0a|"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,8943e71a8c73b5e343aa9d2e19002373; classtype:command-and-control; sid:2024894; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_07_12, deployment Perimeter, confidence High, signature_severity Major, tag Targeted, tag c2, updated_at 2020_08_12, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)