ET POLICY External IP Address Request via wttr .in

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET POLICY External IP Address Request via wttr .in";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/?format="; startswith;
    http.host;
    content:"wttr.in"; endswith; fast_pattern;
    http.header_names;
    content:!"Referer";
    classtype:policy-violation;
    sid:2033354; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2021_07_16, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_16;
)