alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE GanDownloader CnC Checkin"; flow:established,to_server; http.request_body; content:"|2f 00 00 00|"; depth:4; content:"_"; distance:6; content:"202020202020|00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|"; endswith; fast_pattern; pcre:"/^\x2f\x00{3}[A-Z0-9]{6}_[a-f0-9]+\x00{16}$/s"; http.request_line; content:"POST / HTTP/1.1"; depth:15; http.header_names; content:!"Accept"; content:!"User-Agent"; content:!"Referer"; reference:md5,8f0017ed89c2f6639cc2a08bc1e83f1e; classtype:command-and-control; sid:2026946; rev:6; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_02_20, deployment Perimeter, deprecation_reason Age, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2023_12_19, reviewed_at 2023_12_19;)