alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT Nuclear EK Exploit URI Struct Aug 12"; flow:established,to_server; flowbits:set,NuclearEK; urilen:>100; http.uri; content:!"|20|"; content:!"+"; content:!"_"; content:!"-"; pcre:"/\/(?:[^?]+\?)(?=[A-Z&=\d]*?[a-z])(?=[a-zA-Z\d&=]*?[A-Za-z=&]\d[A-Za-z])(?=[a-zA-Z\d&=]*?[a-z\d][A-Z][A-Za-z\d])[A-Za-z0-9]+=[A-Za-z0-9]+&[A-Za-z0-9]+=[A-Za-z0-9]+&[A-Za-z0-9]+=[A-Za-z0-9]+[&=A-Za-z0-9]*?$/"; http.referer; content:"search?q="; fast_pattern; http.header; pcre:"/Referer\x3a\x20http\x3a\x2f+(?!www\.)(?P<refhost>[^\x3a\x2f\r\n]+)[^\r\n]*?\/search\?q=(?=[A-Z&=\d]*?[a-z])(?=[a-zA-Z\d&=]*?[A-Za-z=&]\d[A-Za-z])(?=[a-zA-Z\d&=]*?[a-z\d][A-Z][A-Za-z\d])[A-Za-z0-9]+&[A-Za-z0-9]+=[A-Za-z0-9]+&[A-Za-z0-9]+=[A-Za-z0-9]+&[A-Za-z0-9]+=[A-Za-z0-9]+[&=A-Za-z0-9]*?\r\n.*?Host\x3a\x20(?P=refhost)/si"; http.host; pcre:!"/^(?:[^\r\n]+\.)?(?:ya(?:ndex|hoo)|google|bing)\.(?:com?)?(?:\.[a-z]{2})?$/i"; http.header_names; content:!"|0d 0a|Cookie|0d 0a|"; classtype:exploit-kit; sid:2021620; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2015_08_13, deployment Perimeter, malware_family Nuclear, confidence High, signature_severity Critical, tag Exploit_Kit, tag Nuclear, updated_at 2024_03_03;)