ET EXPLOIT_KIT Underminer EK Key POST

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET EXPLOIT_KIT Underminer EK Key POST";
    flow:to_server,established;
    http.method;
    content:"POST";
    http.uri;
    content:"/";
    content:".html"; distance:26; within:5;
    pcre:"/\/(?![a-z]{26}|[0-9]{26})[a-z0-9]{26}\.html$/i";
    http.header;
    content:"/";
    content:".html"; distance:26; within:5;
    http.referer;
    content:".html"; endswith;
    pcre:"/^[^\r\n]+(?![a-z]{26}|[0-9]{26})[a-z0-9]{26}\.html/";
    http.cookie;
    content:"token="; depth:6;
    http.request_body;
    content:"{|22|mode|22 3a|10,|22|key|22 3a 22|"; nocase; depth:18; fast_pattern;
    http.content_type;
    content:"text/plain|3b|charset=UTF-8";
    classtype:exploit-kit;
    sid:2026421; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_09_27, deployment Perimeter, confidence High, signature_severity Major, tag Underminer_EK, updated_at 2020_08_25;
)