auxiliary(scanner/http/redoc_exposed): detect exposed ReDoc API docs UI

documentation/modules/auxiliary/scanner/http/redoc_exposed.md

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+## Vulnerable Application
+
+Detects publicly exposed ReDoc API documentation pages by looking for known DOM elements and script names. The module
+is read-only and sends safe `GET` requests.
+
+### How It Works
+- Prefers DOM checks (`<redoc>`, `#redoc`, or scripts containing `redoc` / `redoc.standalone`).
+- Falls back to title/body heuristics for “redoc”.
+- Considers only **2xx** and **403** responses (avoids noisy redirects).
+
+## Verification Steps
+
+1. Start `msfconsole`.
+2. `use auxiliary/scanner/http/redoc_exposed`
+3. `set RHOSTS <target-or-range>`
+4. (Optional) `set SSL true`
+5. (Optional) `set REDOC_PATHS /redoc,/docs`
+6. `run`
+
+## Options
+### REDOC_PATHS
+Comma-separated custom paths to probe. If unset, defaults to `/redoc,/redoc/,/docs,/api/docs,/openapi`
+
+## Scenarios
+
+```text
+msf6 > use auxiliary/scanner/http/redoc_exposed
+msf6 auxiliary(scanner/http/redoc_exposed) > set RHOSTS 192.0.2.0/24
+msf6 auxiliary(scanner/http/redoc_exposed) > run
+[+] 192.0.2.15 - ReDoc likely exposed at /docs
+[*] 192.0.2.23 - no ReDoc found
+```
+## Notes
+
+* **Stability**: `CRASH_SAFE` (GET requests only).
+* **Reliability**: No session creation.
+* **SideEffects**: Requests may appear in server logs (`IOC_IN_LOGS`).

modules/auxiliary/scanner/http/redoc_exposed.rb

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+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+class MetasploitModule < Msf::Auxiliary
+  include Msf::Auxiliary::Scanner
+  include Msf::Exploit::Remote::HttpClient
+
+  def initialize(info = {})
+    super(
+      update_info(
+        info,
+        'Name' => 'ReDoc API Docs UI Exposed',
+        'Description' => %q{
+          Detects publicly exposed ReDoc API documentation pages.
+          The module performs safe, read-only GET requests and reports likely
+          ReDoc instances based on HTML markers.
+        },
+        'Author' => [
+          'Hamza Sahin (@hamzasahin61)'
+        ],
+        'License' => MSF_LICENSE,
+        'Notes' => {
+          'Stability' => [CRASH_SAFE],  # GET requests only; should not crash or disrupt the target service
+          'Reliability' => [],          # Does not establish sessions; leaving this empty is acceptable
+          'SideEffects' => [IOC_IN_LOGS] # Requests may be logged by the target web server
+        },
+        'DefaultOptions' => {
+          'RPORT' => 80
+        }
+      )
+    )
+
+    register_options(
+      [
+        # Mark as required and surface the built-in defaults here
+        OptString.new('REDOC_PATHS', [
+          true,
+          'Comma-separated list of paths to probe',
+          '/redoc,/redoc/,/docs,/api/docs,/openapi'
+        ])
+      ]
+    )
+  end
+
+  # returns true if the response looks like a ReDoc page
+  def redoc_like?(res)
+    # Accept only 2xx or 403 (exclude redirects; many 3xx lack HTML to analyze)
+    return false unless res && (res.code.between?(200, 299) || res.code == 403)
+
+    # Prefer DOM checks
+    doc = res.get_html_document
+    if doc && (doc.at_css('redoc, redoc-, #redoc') ||
+               doc.css('script[src*="redoc"]').any? ||
+               doc.css('script[src*="redoc.standalone"]').any?)
+      return true
+    end
+
+    # Fallback to body/title heuristics
+    title = res.get_html_title.to_s
+    body = res.body.to_s
+    return true if title =~ /redoc/i || body =~ /<redoc-?/i || body =~ /redoc(\.standalone)?\.js/i
+
+    false
+  end
+
+  def check_path(path)
+    redoc_like?(send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(path) }))
+  end
+
+  def run_host(ip)
+    vprint_status("#{ip} - scanning for ReDoc")
+
+    # REDOC_PATHS is required and has defaults; always use it directly
+    paths = datastore['REDOC_PATHS'].split(',').map(&:strip)
+
+    hit = paths.find { |p| check_path(p) }
+    if hit
+      print_good("#{ip} - ReDoc likely exposed at #{hit}")
+      report_service(host: ip, port: rport, proto: 'tcp', name: 'http')
+    else
+      vprint_status("#{ip} - no ReDoc found")
+    end
+  end
+end