ET MALWARE Cobalt Strike Malleable C2 (Unknown Profile)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Cobalt Strike Malleable C2 (Unknown Profile)";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/_/scs/mail-static/_/js/"; bsize:24; fast_pattern;
    http.header;
    content:"Accept|3a 20|text/html,application/xhtml+xml,application/xml|3b|q=0.9,*/*|3b|q=0.8|0d 0a|Accept-Language|3a 20|en-US,en|3b|q=0.5|0d 0a|Accept-Encoding|3a 20|gzip, deflate|0d 0a|DNT|3a 20|1|0d 0a|";
    http.cookie;
    content:"OSID="; startswith;
    pcre:"/^OSID=[a-zA-Z0-9\/+]{171}=$/";
    reference:md5,b210c0f7687a9199de870e0cc11996c1;
    classtype:command-and-control;
    sid:2032953; rev:2;
    metadata:attack_target Client_Endpoint, created_at 2021_05_13, deployment Perimeter, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2021_05_14, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;
)