""ET EXPLOIT Apache log4j RCE Attempt - lower/upper TCP Bypass M1 (CVE-2021-44228)""

SID: 2034659

Revision: 2

Class Type: attempted-admin

Metadata: attack_target Server, created_at 2021_12_11, cve CVE_2021_44228, deployment Perimeter, deployment Internal, signature_severity Major, tag Exploit, updated_at 2021_12_14, 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: any

Source Port: any

Destination Network: [$HOME_NET,$HTTP_SERVERS]

Destination Port: any

Flow: established,to_server

Contents:

  • Value: "%7bjndi%3a"

Within:

PCRE: "/^(l|r|d|(\x24|%24)(\x7b|%7b)(lower|upper)(\x3a|%3a)(l|r|d)(\x7d|%7d))(d|n|m|(\x24|%24)(\x7b|%24)(lower|upper)(\x3a|%3a)(d|n|m)(\x7d|%7d))(a|i|s|(\x24|%24)(\x7b|%7b)(lower|upper)(\x3a|%3a)(a|i|s)(\x7d|%7d))(p|(\x24|%24)(\x7b|%7b)(lower|upper)(\x3a|%3a)p(\x7d|%7d))/Ri"

Special Options:

  • nocase

  • fast_pattern

source