ET MALWARE Zacom/NFlog HTTP POST Connectivity Check

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Zacom/NFlog HTTP POST Connectivity Check";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/STTip.asp"; fast_pattern;
    http.content_len;
    byte_test:0,=,0,0,string,dec;
    http.header_names;
    content:!"Accept-";
    content:!"Content-Type|0d 0a|";
    content:!"Referer|0d 0a|";
    reference:url,researchcenter.paloaltonetworks.com/2015/04/unit-42-identifies-new-dragonok-backdoor-malware-deployed-against-japanese-targets/;
    classtype:trojan-activity;
    sid:2020924; rev:4;
    metadata:created_at 2015_04_16, signature_severity Major, updated_at 2020_05_21;
)