alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT Nuclear EK Silverlight URI Struct"; flow:established,to_server; content:".xap"; http_uri; fast_pattern; content:"/1"; http_uri; pcre:"/\/1(?:3[89]\d{7}|4\d{8})\.xap$/U"; classtype:exploit-kit; sid:2019167; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2014_09_12, deployment Perimeter, malware_family Nuclear, confidence High, signature_severity Critical, tag Exploit_Kit, tag Nuclear, updated_at 2019_10_08;)