alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT28/Sofacy Zebrocy Secondary Payload CnC Checkin"; flow:established,to_server; urilen:1; http.method; content:"POST"; http.user_agent; content:"Go-http-client/"; depth:15; fast_pattern; http.request_body; content:"l="; depth:2; content:!"%"; http.header_names; content:!"Referer"; reference:url,unit42.paloaltonetworks.com/sofacy-creates-new-go-variant-of-zebrocy-tool; reference:md5,3773150aeee03783a6da0820a8feb752; classtype:targeted-activity; sid:2026754; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_01_03, deployment Perimeter, malware_family Zebrocy, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2020_08_27;)