alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET ATTACK_RESPONSE Koi Loader/Stealer CnC Config Inbound"; flow:established,to_client; http.response_body; bsize:<65; content:"|2e|php|7c|"; endswith; fast_pattern; pcre:"/^[a-zA-Z0-9]{20}\x7c[a-zA-Z0-9]{8}\x7chttps?\x3a\x2f\x2f[a-zA-Z0-9\x2e\x2f]{1,}\x2ephp\x7c$/"; reference:url,malware-traffic-analysis.net/2025/01/23/index.html; classtype:trojan-activity; sid:2059745; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state plaintext, created_at 2025_01_29, deployment Perimeter, malware_family KoiStealer, performance_impact Moderate, confidence Medium, signature_severity Major, updated_at 2025_01_29, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1105, mitre_technique_name Ingress_Tool_Transfer; target:dest_ip;)