title: Log4j RCE CVE-2021-44228 Generic
id: 5ea8faa8-db8b-45be-89b0-151b84c82702
status: test
description: Detects exploitation attempt against log4j RCE vulnerability reported as CVE-2021-44228 (Log4Shell)
references:
    - https://web.archive.org/web/20231230220738/https://www.lunasec.io/docs/blog/log4j-zero-day/
    - https://news.ycombinator.com/item?id=29504755
    - https://github.com/tangxiaofeng7/apache-log4j-poc
    - https://gist.github.com/Neo23x0/e4c8b03ff8cdf1fa63b7d15db6e3860b
    - https://github.com/YfryTchsGD/Log4jAttackSurface
    - https://twitter.com/shutingrz/status/1469255861394866177?s=21
author: Florian Roth (Nextron Systems)
date: 2021-12-10
modified: 2022-02-06
tags:
    - attack.initial-access
    - attack.t1190
    - detection.emerging-threats
logsource:
    category: webserver
detection:
    keywords:
        - '${jndi:ldap:/'
        - '${jndi:rmi:/'
        - '${jndi:ldaps:/'
        - '${jndi:dns:/'
        - '/$%7bjndi:'
        - '%24%7bjndi:'
        - '$%7Bjndi:'
        - '%2524%257Bjndi'
        - '%2F%252524%25257Bjndi%3A'
        - '${jndi:${lower:'
        - '${::-j}${'
        - '${jndi:nis'
        - '${jndi:nds'
        - '${jndi:corba'
        - '${jndi:iiop'
        - 'Reference Class Name: foo'
        - '${${env:BARFOO:-j}'
        - '${::-l}${::-d}${::-a}${::-p}'
        - '${base64:JHtqbmRp'
        - '${${env:ENV_NAME:-j}ndi${env:ENV_NAME:-:}$'
        - '${${lower:j}ndi:'
        - '${${upper:j}ndi:'
        - '${${::-j}${::-n}${::-d}${::-i}:'
    filter:
        - 'w.nessus.org/nessus'
        - '/nessus}'
    condition: keywords and not filter
falsepositives:
    - Vulnerability scanning
level: high