ET MALWARE Possible Sharik/Smoke Loader Microsoft Connectivity check

Query · suricata

flow:established,to_server;
http.method;
content:"GET";
http.uri;
content:"/kb/"; depth:4; fast_pattern;
pcre:"/^\d{4,8}$/R";
http.user_agent;
content:!"Microsoft Outlook";
http.header_names;
content:!"Referer";
content:"User-Agent";
content:!"Accept";
Raw source ET MALWARE Possible Sharik/Smoke Loader Microsoft Connectivity check · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Possible Sharik/Smoke Loader Microsoft Connectivity check";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/kb/"; depth:4; fast_pattern;
    pcre:"/^\d{4,8}$/R";
    http.user_agent;
    content:!"Microsoft Outlook";
    http.header_names;
    content:!"Referer";
    content:"User-Agent";
    content:!"Accept";
    reference:md5,7e604b9e059d054d58c91330d4d88c62;
    classtype:trojan-activity;
    sid:2025120; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_12_05, deployment Perimeter, confidence Medium, signature_severity Major, tag Smoke_Loader, updated_at 2020_08_24;
)

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