alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT Nuclear EK CVE-2013-2551 URI Struct Nov 26 2013"; flow:established,to_server; content:".htm"; http_uri; fast_pattern; pcre:"/^\/\d{8,11}(\/\d)?\/1[34]\d{8}\.htm$/U"; pcre:"/^Referer\x3a[^\r\n]+?\/[a-f0-9A-Z\_\-]{32,}\.html(?:\x3a\d{1,5})?\r$/Hm"; flowbits:set,et.exploitkitlanding; classtype:exploit-kit; sid:2017774; rev:10; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2013_11_27, deployment Perimeter, malware_family Nuclear, confidence High, signature_severity Critical, tag Exploit_Kit, tag Nuclear, tag CISA_KEV, updated_at 2019_10_08;)