ET MALWARE Possible Dyre SSL Cert M3 (O CN)

alert tls $EXTERNAL_NET [443,4443] -> $HOME_NET any (
    msg:"ET MALWARE Possible Dyre SSL Cert M3 (O CN)";
    flow:established,to_client;
    tls.cert_serial;
    content:"00:"; startswith; bsize:26;
    tls.certs;
    content:"|06 03 55 04 06 13 02|";
    pcre:"/^[A-Z]{2}[01]/R";
    content:"|30 09 06 03 55 04 08 0c 02|"; distance:1; within:9; fast_pattern;
    pcre:"/^[A-Z]{2}[01]/R";
    content:"|06 03 55 04 07 0c|"; distance:0;
    content:"|06 03 55 04 0a 0c|"; distance:0;
    byte_extract:1,0,orglen,relative;
    content:!"|20|"; within:orglen;
    pcre:"/^(?=[a-z0-9]{0,119}[A-Z])(?=[A-Z0-9]{0,119}[a-z])[a-zA-Z0-9]{10,120}[01]/R";
    content:"|06 03 55 04 03 0c|"; within:9;
    byte_extract:1,0,cnlen,relative;
    content:!"|2e|"; within:cnlen;
    content:!"|2a|"; within:cnlen;
    pcre:"/^(?=[a-z0-9]{0,119}[A-Z])(?=[A-Z0-9]{0,119}[a-z])(?P<var>[a-zA-Z0-9]{10,120}[01]).+?\x55\x04\x03.{2}(?P=var)/Rs";
    classtype:trojan-activity;
    sid:2021434; rev:5;
    metadata:attack_target Client_Endpoint, created_at 2015_07_17, deployment Perimeter, confidence Medium, signature_severity Major, tag SSL_Malicious_Cert, updated_at 2022_03_27;
)