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

SID: 2034800

Revision: 2

Class Type: attempted-admin

Metadata: attack_target Server, created_at 2021_12_17, cve CVE_2021_44228, deployment Perimeter, deployment Internal, signature_severity Major, tag Exploit, 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

Reference:

  • cve

  • 2021-44228

Protocol: tcp

Source Network: $HOME_NET

Source Port: any

Destination Network: any

Destination Port: any

Flow: established,to_server

Contents:

  • Value: "|24 7b|jndi|3a|"

  • Value: "|3a 2f 2f|"

Within:

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"

Special Options:

  • nocase

  • fast_pattern

source