ET WEB_CLIENT Inbound JS with Possible 1px-1px Exfiltration Image

Query · suricata

flow:established,to_client;
http.stat_code;
content:"200";
file.data;
content:"document.createElement|28 22|";
content:".width=|22|1px|22|"; within:30;
content:".height=|22|1px|22|"; within:30;
content:"atob|28 22|aHR0c"; within:100; fast_pattern;
pcre:"/^(?:HM6Ly|DovL)/R";
target:dest_ip;
Raw source ET WEB_CLIENT Inbound JS with Possible 1px-1px Exfiltration Image · 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 WEB_CLIENT Inbound JS with Possible 1px-1px Exfiltration Image";
    flow:established,to_client;
    http.stat_code;
    content:"200";
    file.data;
    content:"document.createElement|28 22|";
    content:".width=|22|1px|22|"; within:30;
    content:".height=|22|1px|22|"; within:30;
    content:"atob|28 22|aHR0c"; within:100; fast_pattern;
    pcre:"/^(?:HM6Ly|DovL)/R";
    reference:url,www.symantec.com/content/dam/symantec/docs/security-center/white-papers/istr-formjacking-deep-dive-en.pdf;
    classtype:trojan-activity;
    sid:2027817; rev:4;
    metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2019_08_07, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence Medium, signature_severity Major, tag CardSkimmer, updated_at 2026_07_31, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1189, mitre_technique_name Drive_by_Compromise;
    target:dest_ip;
)

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