ET MALWARE Linux/Moose NAT Traversal CnC Beacon set

alert tcp $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Linux/Moose NAT Traversal CnC Beacon set";
    flow:established,to_server;
    dsize:4;
    content:"|18 00 00 00|"; fast_pattern;
    flowbits:set,ET.Linux.Moose;
    flowbits:noalert;
    reference:url,welivesecurity.com/wp-content/uploads/2015/05/Dissecting-LinuxMoose.pdf;
    classtype:command-and-control;
    sid:2021150; rev:2;
    metadata:attack_target Client_Endpoint, created_at 2015_05_26, deployment Perimeter, signature_severity Major, tag c2, updated_at 2019_10_08, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;
)