ET MALWARE Win32/Emotet CnC Checkin (POST)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Emotet CnC Checkin (POST)";
    flow:established,to_server;
    urilen:1;
    flowbits:set,ETPRO.Emotet;
    http.method;
    content:"POST";
    http.request_body;
    pcre:"/^[\x20-\x7e\r\n]{0,20}[^\x20-\x7e\r\n]/s";
    http.user_agent;
    content:"Mozilla/4.0 (compatible|3b 20|MSIE 7.0|3b 20|Windows NT 6.1|3b 20|"; depth:51;
    pcre:"/^(?:WOW64\x3b\s)?Trident\/[457]\.0\x3b\s*SLCC2\x3b\s\.NET\sCLR\s2\.0\.50727\x3b\s\.NET\sCLR\s3\.5\.30729\x3b\s(?:\x20\.NET\x20CLR\x203\.5\.30729\x3b\s)?\.NET\sCLR\s3\.0\.30729\x3b\sMedia\sCenter\sPC\s6\.0\x3b\s\.NET4\.0C\x3b\s\.NET4\.0E(?:\.NET4\.0E(?:\x3b\s)?)?(?:\x3b\sInfoPath\.3)?\)$/Rs";
    http.start;
    content:"POST|20|/|20|HTTP/1.1|0d 0a|";
    http.header_names;
    content:"|0d 0a|User-Agent|0d 0a|Host|0d 0a|Content-Length|0d 0a|Connection|0d 0a|Cache-Control|0d 0a 0d 0a|"; fast_pattern; depth:65;
    content:!"Referer";
    content:!"Accept";
    classtype:command-and-control;
    sid:2035053; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_06_11, deployment Perimeter, malware_family Emotet, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2020_08_25;
)