ET EXPLOIT Possible Apache log4j RCE Attempt - 2021/12/13 Obfuscation Observed (tcp) (Outbound) (CVE-2021-44228)

Query · suricata

flow:established,to_server;
content:"|24 7b|";
pcre:"/^(j|\x24\x7b(lower|upper)\x3aj\x7d|\x24\x7b\x3a\x3a\-j\x7d)(n|\x24\x7b(lower|upper)\x3an\x7d|\x24\x7b\x3a\x3a\-n\x7d)/Ri";
content:"|3a|"; distance:0;
content:"|24 7b|env|3a|"; distance:0;
Raw source ET EXPLOIT Possible Apache log4j RCE Attempt - 2021/12/13 Obfuscation Observed (tcp) (Outbound) (CVE-2021-44228) · 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 tcp $HOME_NET any -> any any (
    msg:"ET EXPLOIT Possible Apache log4j RCE Attempt - 2021/12/13 Obfuscation Observed (tcp) (Outbound) (CVE-2021-44228)";
    flow:established,to_server;
    content:"|24 7b|";
    pcre:"/^(j|\x24\x7b(lower|upper)\x3aj\x7d|\x24\x7b\x3a\x3a\-j\x7d)(n|\x24\x7b(lower|upper)\x3an\x7d|\x24\x7b\x3a\x3a\-n\x7d)/Ri";
    content:"|3a|"; distance:0;
    content:"|24 7b|env|3a|"; distance:0;
    reference:cve,2021-44228;
    classtype:attempted-admin;
    sid:2034806; rev:2;
    metadata:attack_target Server, created_at 2021_12_18, cve CVE_2021_44228, deployment Perimeter, deployment Internal, confidence Medium, signature_severity Major, tag Exploit, tag CISA_KEV, updated_at 2021_12_18, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
)

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