open-proxy-localhost: Open Proxy to Other Web Ports via Proxy's localhost Interface

id: open-proxy-localhost

info:
  name: Open Proxy to Other Web Ports via Proxy's localhost Interface
  author: sullo
  severity: high
  description: The host is configured as a proxy which allows access to web ports on the host's internal interface.
  remediation: Disable the proxy or restrict configuration to only allow access to approved hosts/ports.
  reference:
    - https://blog.projectdiscovery.io/abusing-reverse-proxies-internal-access/
    - https://en.wikipedia.org/wiki/Open_proxy
    - https://www.acunetix.com/vulnerabilities/web/apache-configured-to-run-as-proxy/
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
    cvss-score: 8.6
    cwe-id: CWE-441
  metadata:
    max-request: 6
  tags: exposure,config,proxy,misconfig,fuzz,vuln

http:
  - raw:
      - |+
        GET / HTTP/1.1
        Host: {{Hostname}}

      - |+
        GET http://somethingthatdoesnotexist/ HTTP/1.1
        Host: somethingthatdoesnotexist

      - |+
        GET http://127.0.0.1/ HTTP/1.1
        Host: 127.0.0.1

      - |+
        GET https://127.0.0.1/ HTTP/1.1
        Host: 127.0.0.1

      - |+
        GET http://localhost/ HTTP/1.1
        Host: localhost

      - |+
        GET https://localhost/ HTTP/1.1
        Host: localhost

    unsafe: true
    stop-at-first-match: true
    matchers:
      - type: dsl
        condition: or
        dsl:
          - (!contains(body_1, "<title>IIS7</title>") && !contains(body_2, "<title>IIS7</title>")) && (contains(body_3, "<title>IIS7</title>") || contains(body_4, "<title>IIS7</title>") || contains(body_5, "<title>IIS7</title>") || contains(body_6, "<title>IIS7</title>"))
          - (!contains(body_1, "503 Service Unavailable") && !contains(body_2, "503 Service Unavailable")) && (contains(body_3, "503 Service Unavailable") || contains(body_4, "503 Service Unavailable") || contains(body_5, "503 Service Unavailable") || contains(body_6, "503 Service Unavailable"))
          - (!contains(body_1, "default welcome page") && !contains(body_2, "default welcome page")) && (contains(body_3, "default welcome page") || contains(body_4, "default welcome page") || contains(body_5, "default welcome page") || contains(body_6, "default welcome page"))
          - (!contains(body_1, "IIS Windows Server") && !contains(body_2, "IIS Windows Server")) && (contains(body_3, "IIS Windows Server") || contains(body_4, "IIS Windows Server") || contains(body_5, "IIS Windows Server") || contains(body_6, "IIS Windows Server"))
          - (!contains(body_1, "Microsoft Azure App") && !contains(body_2, "Microsoft Azure App")) && (contains(body_3, "Microsoft Azure App") || contains(body_4, "Microsoft Azure App") || contains(body_5, "Microsoft Azure App") || contains(body_6, "Microsoft Azure App"))
          - (!contains(body_1, "Welcome to IIS") && !contains(body_2, "Welcome to IIS")) && (contains(body_3, "Welcome to IIS") || contains(body_4, "Welcome to IIS") || contains(body_5, "Welcome to IIS") || contains(body_6, "Welcome to IIS"))
          - (!contains(body_1, "Welcome to Microsoft Windows") && !contains(body_2, "Welcome to Microsoft Windows")) && (contains(body_3, "Welcome to Microsoft Windows") || contains(body_4, "Welcome to Microsoft Windows") || contains(body_5, "Welcome to Microsoft Windows") || contains(body_6, "Welcome to Microsoft Windows"))
          - (!contains(body_1, "Welcome to Windows") && !contains(body_2, "Welcome to Windows")) && (contains(body_3, "Welcome to Windows") || contains(body_4, "Welcome to Windows") || contains(body_5, "Welcome to Windows") || contains(body_6, "Welcome to Windows"))
          - (!contains(body_1, "Welcome to Windows") && !contains(body_2, "Welcome to Windows")) && (contains(body_3, "Welcome to Windows") || contains(body_4, "Welcome to Windows") || contains(body_5, "Welcome to Windows") || contains(body_6, "Welcome to Windows"))
          - (!contains(body_1, "It works") && !contains(body_2, "It works")) && (contains(body_3, "It works") || contains(body_4, "It works") || contains(body_5, "It works") || contains(body_6, "It works"))
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