alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT Nuclear EK PDF URI Struct"; flow:established,to_server; flowbits:set,et.exploitkitlanding; http.uri; content:".pdf"; fast_pattern; content:"/1"; pcre:"/\/1(?:3[89]\d{7}|4\d{8})\.pdf$/"; http.header; pcre:"/^Referer\x3a[^\r\n]+?\/[a-z0-9A-Z\_\-]{26,}\.html(?:\x3a\d{1,5})?\r$/m"; classtype:exploit-kit; sid:2017636; rev:15; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2013_10_28, deployment Perimeter, deprecation_reason Age, malware_family Nuclear, confidence High, signature_severity Critical, tag Exploit_Kit, tag Nuclear, updated_at 2024_02_08, reviewed_at 2024_02_08;)