alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET RETIRED Win32/Koi Loader CnC Checkin M2"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/config.php"; http.content_type; content:"application/octet-stream"; http.header; content:"Content-Encoding|3a 20|binary|0d 0a|"; http.content_len; byte_test:0,=,86,0,string,dec; http.request_body; content:"111|7c|"; startswith; fast_pattern; pcre:"/^[a-f0-9]{8}-([a-f0-9]{4}-){3}[a-f0-9]{12}\x7c/R"; reference:md5,09350493580399e2983148e80fd4490b; classtype:trojan-activity; sid:2049814; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_Endpoint, created_at 2023_12_21, deployment Perimeter, former_category MALWARE, malware_family Win32_Koi, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_04_17, reviewed_at 2025_04_17; target:src_ip;)