alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Koadic Header Structure"; flow:established,to_server; http.header; content:"|0d 0a|encoder|3a 20|"; content:"|0d 0a|shellchpc|3a 20|"; distance:0; fast_pattern; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; reference:md5,1e1afc93c8092b2c7e49a6d3a451629f; classtype:trojan-activity; sid:2030341; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_06_15, deployment Perimeter, malware_family Koadic, confidence High, signature_severity Major, updated_at 2024_04_20;)