Rule History

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;)