ET WEB_CLIENT Spectre Exploit Javascript

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET WEB_CLIENT Spectre Exploit Javascript";
    flow:from_server,established;
    file_data;
    content:"0x1000000"; fast_pattern;
    pcre:"/(?<var1>[^=\s]*)\s*=\s*0x1000000.+?\x28\s*\x28\s*\x28\s*\w+\s*<<\s*12\s*\x29\s*\|\s*0\s*\x29\s*\+\s*(?P=var1)\s*\x29\s*\|\s*0/s";
    reference:cve,2017-5753;
    reference:cve,2017-5715;
    reference:url,github.com/cgvwzq/spectre;
    classtype:attempted-user;
    sid:2025188; rev:6;
    metadata:affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2018_01_09, cve CVE_2017_5753, deployment Perimeter, performance_impact Moderate, signature_severity Major, tag Web_Client_Attacks, updated_at 2019_10_08;
)