ET POLICY localtunnel Connection Setup Attempt

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET POLICY localtunnel Connection Setup Attempt";
    flow:established,to_server;
    http.host;
    content:"localtunnel.me"; fast_pattern; endswith;
    http.header_names;
    content:"|0d 0a|host|0d 0a|accept"; depth:14;
    content:!"User-Agent";
    content:!"Host";
    content:!"Referer";
    content:!"Accept";
    reference:url,localtunnel.github.io/www/;
    classtype:policy-violation;
    sid:2025116; rev:4;
    metadata:attack_target Client_and_Server, created_at 2017_12_04, deployment Perimeter, confidence High, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_16;
)