ET MALWARE OSX/SHLAYER CnC Checkin

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE OSX/SHLAYER CnC Checkin";
    flow:established,to_server;
    http.request_line;
    content:"POST http://"; fast_pattern;
    http.uri;
    content:"/l"; bsize:2;
    http.host;
    content:"api."; startswith;
    http.header_names;
    content:"|0d 0a|Host|0d 0a|Content-Length|0d 0a|Content-Type|0d 0a|Accept|0d 0a|Connection|0d 0a 0d 0a|";
    content:!"User-Agent";
    content:!"Referer";
    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;
    reference:md5,4d86ae25913374cfcb80a8d798b9016e;
    reference:url,securelist.com/shlayer-for-macos/95724/;
    classtype:command-and-control;
    sid:2030231; rev:5;
    metadata:affected_product Mac_OSX, attack_target Client_Endpoint, created_at 2020_05_29, deployment Perimeter, malware_family OSX_SHLAYER, performance_impact Moderate, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_04;
)