ET MALWARE Observed Default CobaltStrike SSL Certificate

alert tls $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE Observed Default CobaltStrike SSL Certificate";
    flow:established,to_client;
    tls.cert_issuer;
    content:"C=Earth"; nocase;
    content:"ST=Cyberspace"; nocase;
    content:"L=Somewhere"; nocase;
    content:"O=cobaltstrike"; nocase;
    content:"OU=AdvancedPenTesting"; nocase;
    content:"CN=Major Cobalt Strike"; nocase; fast_pattern;
    reference:url,fireeye.com/blog/threat-research/2020/03/the-cycle-of-adversary-pursuit.html;
    classtype:trojan-activity;
    sid:2030111; rev:2;
    metadata:attack_target Client_Endpoint, created_at 2020_05_06, deployment Perimeter, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2021_08_26;
)