ET MALWARE BackConnect CnC Activity (Set Sleep Timer)

alert tcp-pkt $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE BackConnect CnC Activity (Set Sleep Timer)";
    flow:established,to_client;
    flowbits:set,ET.BackConnect;
    content:"|01 3c 00 00 00|"; offset:4; depth:5;
    dsize:13; fast_pattern;
    threshold:type limit,track by_src,count 1,seconds 1800;
    reference:url,netresec.com/?page=Blog&month=2022-10&post=IcedID-BackConnect-Protocol;
    reference:url,twitter.com/netresec/status/1577966512459087874;
    reference:url,twitter.com/Unit42_Intel/status/1577773890012594177;
    classtype:command-and-control;
    sid:2050078; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2024_01_16, deployment Perimeter, malware_family BackConnect, confidence High, signature_severity Critical, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_01_16;
)