alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE JS/Ostap CnC Activity"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php?as="; content:"&kl="; distance:0; content:"&ed="; distance:0; content:"@@"; distance:0; content:"@@"; distance:0; content:"@@*"; fast_pattern; distance:0; http.header_names; content:!"Referer"; reference:md5,f5cf9ca73dd30caf43d75dd19240a79e; classtype:trojan-activity; sid:2030601; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_07_28, deployment Perimeter, malware_family Ostap, confidence High, signature_severity Major, updated_at 2020_07_28;)