ET EXPLOIT Apache log4j RCE Attempt - lower/upper TCP Bypass M2 (Outbound) (CVE-2021-44228)

Query · suricata

flow:established,to_server;
content:"|24 7b|jndi|3a|"; nocase; fast_pattern;
pcre:"/^(l|r|d|\x24\x7b(lower|upper)\x3a(l|r|d)\x7d)(d|n|m|\x24\x7b(lower|upper)\x3a(d|n|m)\x7d)(a|i|s|\x24\x7b(lower|upper)\x3a(a|i|s)\x7d)(p|\x24\x7b(lower|upper)\x3a(p)\x7d)/Ri";
content:"|3a 2f 2f|"; distance:0;
Raw source ET EXPLOIT Apache log4j RCE Attempt - lower/upper TCP Bypass M2 (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 Apache log4j RCE Attempt - lower/upper TCP Bypass M2 (Outbound) (CVE-2021-44228)";
    flow:established,to_server;
    content:"|24 7b|jndi|3a|"; nocase; fast_pattern;
    pcre:"/^(l|r|d|\x24\x7b(lower|upper)\x3a(l|r|d)\x7d)(d|n|m|\x24\x7b(lower|upper)\x3a(d|n|m)\x7d)(a|i|s|\x24\x7b(lower|upper)\x3a(a|i|s)\x7d)(p|\x24\x7b(lower|upper)\x3a(p)\x7d)/Ri";
    content:"|3a 2f 2f|"; distance:0;
    reference:cve,2021-44228;
    classtype:attempted-admin;
    sid:2034800; rev:2;
    metadata:attack_target Server, created_at 2021_12_17, cve CVE_2021_44228, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Exploit, tag CISA_KEV, updated_at 2021_12_17, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
)

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