ET MALWARE DeerStealer POST Request containing Base64 Encoded 64 Byte String

Query · suricata

flow:established,to_server;
http.method;
content:"POST";
http.connection;
content:"Keep-Alive";
http.header_names;
content:"|0d 0a|connection|0d 0a|accept|0d 0a|user-agent|0d 0a|content-length|0d 0a|host|0d 0a 0d 0a|"; fast_pattern; nocase;
http.uri;
content:"|3d|";
base64_decode:offset 0,relative;
base64_data; bsize:64;
target:src_ip;
Raw source ET MALWARE DeerStealer POST Request containing Base64 Encoded 64 Byte String · Suricata
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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 -> any any (
    msg:"ET MALWARE DeerStealer POST Request containing Base64 Encoded 64 Byte String";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.connection;
    content:"Keep-Alive";
    http.header_names;
    content:"|0d 0a|connection|0d 0a|accept|0d 0a|user-agent|0d 0a|content-length|0d 0a|host|0d 0a 0d 0a|"; fast_pattern; nocase;
    http.uri;
    content:"|3d|";
    base64_decode:offset 0,relative;
    base64_data; bsize:64;
    reference:url,any.run/cybersecurity-blog/deerstealer-campaign-analysis/;
    classtype:trojan-activity;
    sid:2061611; rev:1;
    metadata:attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2025_04_15, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, updated_at 2025_04_15;
    target:src_ip;
)

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