ET MALWARE Observed Malicious SSL Cert (Issuer contains CN=c2server)

Query · suricata

flow:established,to_client;
tls.cert_issuer;
content:"c2server"; nocase; fast_pattern;
pcre:"/CN=(?:[^\r\n]+?\.)?c2server(?!\.)/i";
Raw source ET MALWARE Observed Malicious SSL Cert (Issuer contains CN=c2server) · 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 Observed Malicious SSL Cert (Issuer contains CN=c2server)";
    flow:established,to_client;
    tls.cert_issuer;
    content:"c2server"; nocase; fast_pattern;
    pcre:"/CN=(?:[^\r\n]+?\.)?c2server(?!\.)/i";
    reference:url,github.com/trickster0/NamelessC2/tree/d075534d4be70fed2e0d3f85c8e90ccc7ac5bc85/NamelessServer;
    classtype:domain-c2;
    sid:2056383; rev:1;
    metadata:attack_target Client_and_Server, created_at 2024_10_01, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_10_01, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;
)

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