alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Nuclear Checkin"; flow:established,to_server; http.uri; content:".htm"; http.user_agent; content:"Mozilla/4.0 (compatible|3b 20|MSIE 6.0|3b 20|Win32)"; http.header; content:"HOST|3A 20|"; reference:md5,bd4af162f583899eeb6ce574863b4db6; classtype:command-and-control; sid:2014121; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2012_01_12, deployment Perimeter, malware_family Nuclear, signature_severity Critical, tag Exploit_Kit, tag Nuclear, updated_at 2020_04_21;)