ET MALWARE OSX/SHLAYER CnC Activity M2

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE OSX/SHLAYER CnC Activity M2";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/l"; bsize:2;
    http.user_agent;
    content:"|20 28|unknown|20|version|29 20|CFNetwork|2f|"; fast_pattern;
    http.request_body;
    content:"cs="; startswith;
    pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})/R";
    http.content_type;
    content:"application/x-www-form-urlencoded"; bsize:33;
    threshold:type limit, count 1, seconds 600, track by_dst;
    classtype:trojan-activity;
    sid:2038612; rev:1;
    metadata:affected_product Mac_OSX, attack_target Client_Endpoint, created_at 2022_08_25, deployment Perimeter, malware_family Shlayer, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_08_25;
)