ET MALWARE Kimsuky Related CnC Activity

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Kimsuky Related CnC Activity";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"|2e|php?dhk="; fast_pattern;
    content:"&user="; distance:0;
    http.header;
    content:"Connection|3a 20|Keep-Alive"; nocase;
    http.header_names;
    content:!"Referer";
    reference:url,github.com/eset/malware-ioc/tree/master/kimsuky/hotdoge_donutcat_case;
    classtype:trojan-activity;
    sid:2034691; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_12_13, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_12_13;
)