ET MALWARE Possible DEEP PANDA C2 Activity

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Possible DEEP PANDA C2 Activity";
    flow:established,to_server;
    http.user_agent;
    content:"Mozilla/4.0+(compatible|3b|+MSIE+8.0|3b|+Windows+NT+5.1|3b|+SV1)"; fast_pattern;
    http.header_names;
    content:!"Referer|0d 0a|";
    content:!"Content-Type|0d 0a|";
    content:!"Accept";
    http.request_body;
    content:"|00 00 00 00 00|";
    classtype:command-and-control;
    sid:2020373; rev:6;
    metadata:created_at 2015_02_06, confidence Medium, signature_severity Major, updated_at 2020_05_15;
)