VMware vSphere Client (HTML5) - Remote Code Execution

Exploited in the wild. Listed by CISA on 2021-11-03; known to be used by ransomware.

criticalseverity

9.8CVSS score

99.9%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

VMware vCenter vSphere Client (HTML5) contains a remote code execution vulnerability in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server. This affects VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).

Impact

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the affected system.

Fix

Apply the necessary security patches or updates provided by VMware to mitigate this vulnerability.

How to confirm it

Send: GET {{BaseURL}}/ui/vropspluginui/rest/services/getstatus
Positive when: contains in header "VSPHERE-UI-JSESSIONID" AND matches /(Install|Config) Final Progress/ AND status 200

Run it with nuclei: nuclei -id CVE-2021-21972 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2021-21972

info:
  name: VMware vSphere Client (HTML5) - Remote Code Execution
  author: dwisiswant0
  severity: critical
  description: VMware vCenter vSphere Client (HTML5) contains a remote code execution vulnerability in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server. This affects VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the affected system.
  remediation: |
    Apply the necessary security patches or updates provided by VMware to mitigate this vulnerability.
  reference:
    - https://swarm.ptsecurity.com/unauth-rce-vmware/
    - https://nvd.nist.gov/vuln/detail/CVE-2021-21972
    - https://www.vmware.com/security/advisories/VMSA-2021-0002.html
    - http://packetstormsecurity.com/files/161590/VMware-vCenter-Server-7.0-Arbitrary-File-Upload.html
    - https://github.com/NS-Sp4ce/CVE-2021-21972
  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-2021-21972
    cwe-id: CWE-22
    epss-score: 0.99865
    epss-percentile: 0.99962
    cpe: cpe:2.3:a:vmware:cloud_foundation:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: vmware
    product: cloud_foundation
  tags: cve2021,cve,vmware,rce,vcenter,kev,packetstorm,vkev,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/ui/vropspluginui/rest/services/getstatus"

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - "VSPHERE-UI-JSESSIONID"
        condition: and

      - type: regex
        part: body
        regex:
          - "(Install|Config) Final Progress"

      - type: status
        status:
          - 200

References

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