ET HUNTING Cross-Site POST Requests Without a Content-Type Header

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET HUNTING Cross-Site POST Requests Without a Content-Type Header";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.header_names;
    content:"Content-Length|0d 0a|";
    content:!"Content-Type|0d 0a|";
    http.header;
    content:"Sec-Fetch-Site|3a 20|cross-site"; fast_pattern;
    reference:url,nastystereo.com/security/cross-site-post-without-content-type.html;
    classtype:web-application-attack;
    sid:2059760; rev:1;
    metadata:attack_target Web_Server, tls_state TLSDecrypt, created_at 2025_01_29, deployment Perimeter, deployment SSLDecrypt, confidence Medium, signature_severity Major, updated_at 2025_01_29;
    target:dest_ip;
)