ET EXPLOIT_KIT Underminer EK SWF Request

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET EXPLOIT_KIT Underminer EK SWF Request";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/";
    content:".swf"; distance:26; within:4; endswith;
    pcre:"/\/(?![a-z]{26}|[0-9]{26})[a-z0-9]{26}\.swf$/i";
    http.header;
    content:"/";
    content:".html"; distance:26; within:5;
    content:"x-flash-version|3a 20|";
    http.referer;
    pcre:"/^.+(?![a-z]{26}|[0-9]{26})[a-z0-9]{26}\.html$/i";
    http.cookie;
    content:"token="; depth:6; fast_pattern;
    pcre:"/^[a-f0-9]{32}$/Ri";
    classtype:exploit-kit;
    sid:2026426; rev:3;
    metadata:affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2018_09_28, deployment Perimeter, confidence High, signature_severity Major, tag Underminer_EK, updated_at 2020_09_16;
)