ET MALWARE Cobalt Strike Malleable C2 (Meterpreter)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Cobalt Strike Malleable C2 (Meterpreter)";
    flow:established,to_server;
    http.uri;
    pcre:"/^\/ucD[A-Za-z0-9_\/\-+]{171}$/";
    http.request_line;
    content:"GET|20|/ucD"; fast_pattern;
    content:"|20|HTTP/1.1"; distance:171; within:9;
    http.header_names;
    content:!"Referer";
    reference:url,github.com/rsmudge/Malleable-C2-Profiles/blob/master/APT/meterpreter.profile;
    classtype:command-and-control;
    sid:2029742; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_03_26, deployment Perimeter, malware_family Cobalt_Strike, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2020_11_10, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;
)