ET RETIRED BunnyLoader Initial CnC Checkin Response

Query · suricata

flow:established,to_client;
flowbits:isset,ET.BunnyLoader.Checkin;
http.stat_code;
content:"200";
http.content_len;
byte_test:0,=,11,0,string,dec;
http.response_body;
content:"Connected|0d 0a|"; fast_pattern;
target:dest_ip;

Rule dependencies

⚠ Higher-order rule. It fires on other rules' alerts, not on raw events, so it cannot fire on its own. Deploy the rules it depends on too.

Depends on

Raw source ET RETIRED BunnyLoader Initial CnC Checkin Response · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET RETIRED BunnyLoader Initial CnC Checkin Response";
    flow:established,to_client;
    flowbits:isset,ET.BunnyLoader.Checkin;
    http.stat_code;
    content:"200";
    http.content_len;
    byte_test:0,=,11,0,string,dec;
    http.response_body;
    content:"Connected|0d 0a|"; fast_pattern;
    reference:url,www.zscaler.com/blogs/security-research/bunnyloader-newest-malware-service;
    reference:md5,dbf727e1effc3631ae634d95a0d88bf3;
    classtype:trojan-activity;
    sid:2048398; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_and_Server, created_at 2023_10_04, deployment Perimeter, former_category MALWARE, malware_family BunnyLoader, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_07_14, reviewed_at 2023_10_04;
    target:dest_ip;
)

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