ET MALWARE Win32/Final1stspy CnC Checkin (Reaper/APT37 Stage 1 Payload)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Final1stspy CnC Checkin (Reaper/APT37 Stage 1 Payload)";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:".php?MachineId=";
    content:"&InfoSo="; distance:0;
    content:"&Index="; distance:0;
    content:"&Account="; distance:0;
    content:"&List="; distance:0;
    pcre:"/^(?:[A-Z0-9+/]{4})*(?:[A-Z0-9+/]{2}==|[A-Z0-9+/]{3}=|[A-Z0-9+/]{4})$/Ri";
    http.user_agent;
    content:"Host|20|Process|20|Update"; fast_pattern; endswith;
    http.header_names;
    content:!"Referer";
    reference:url,researchcenter.paloaltonetworks.com/2018/10/unit42-nokki-almost-ties-the-knot-with-dogcall-reaper-group-uses-new-malware-to-deploy-rat/;
    reference:md5,0f1d3ed85fee2acc23a8a26e0dc12e0f;
    reference:md5,a2fe5dcb08ae8b72e8bc98ddc0b918e7;
    classtype:targeted-activity;
    sid:2026431; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_10_01, deployment Perimeter, malware_family Final1stspy, performance_impact Low, confidence High, signature_severity Major, tag APT37, tag ReaperGroup, updated_at 2020_09_16;
)