ET MALWARE Malicious SSL Certificate detected (Cobalt Strike CnC)

Query · suricata

flow:established,to_client;
tls.cert_subject;
content:"CN=Adobe Reader/O=Adobe"; bsize:23; fast_pattern;
tls.cert_issuer;
content:"C=AU, ST=Some-State, L=City, O=Some Company"; bsize:43;
Raw source ET MALWARE Malicious SSL Certificate detected (Cobalt Strike CnC) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert tls $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE Malicious SSL Certificate detected (Cobalt Strike CnC)";
    flow:established,to_client;
    tls.cert_subject;
    content:"CN=Adobe Reader/O=Adobe"; bsize:23; fast_pattern;
    tls.cert_issuer;
    content:"C=AU, ST=Some-State, L=City, O=Some Company"; bsize:43;
    reference:md5,e4224469bd75b63fa0cebd33c53b4d85;
    classtype:domain-c2;
    sid:2029491; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2020_02_18, deployment Perimeter, malware_family Cobalt_Strike, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_02_18, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;
)

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