test: add permissive-cors-credentials fixture (CWE-942)

docs/VULNERABILITY_CATALOG.md

@@ -7,10 +7,10 @@ from each file's header comment, so this page cannot drift from the source.
 
 ## Totals
 
-- **Test cases:** 116
-- **Expected detections:** 116
-- **`VULNERABLE:` markers:** 215 (individual lines a scanner should flag)
-- **`SAFE:` markers:** 131 (lines a scanner must not flag — the false-positive control group)
+- **Test cases:** 117
+- **Expected detections:** 117
+- **`VULNERABLE:` markers:** 217 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 132 (lines a scanner must not flag — the false-positive control group)
 - **Languages:** 8 — dotenv, go, java, javascript, json, python, ruby, text
 - **CWE categories:** 84 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-94, CWE-95, CWE-113, CWE-117, CWE-129, CWE-190, CWE-201, CWE-203, CWE-208, CWE-209, CWE-256, CWE-287, CWE-288, CWE-291, CWE-295, CWE-306, CWE-307, CWE-319, CWE-321, CWE-326, CWE-327, CWE-329, CWE-330, CWE-338, CWE-345, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-400, CWE-434, CWE-441, CWE-460, CWE-472, CWE-475, CWE-480, CWE-488, CWE-489, CWE-502, CWE-506, CWE-509, CWE-512, CWE-521, CWE-525, CWE-532, CWE-598, CWE-601, CWE-602, CWE-611, CWE-613, CWE-614, CWE-620, CWE-639, CWE-640, CWE-643, CWE-681, CWE-693, CWE-732, CWE-759, CWE-776, CWE-798, CWE-835, CWE-862, CWE-863, CWE-915, CWE-916, CWE-918, CWE-922, CWE-942, CWE-943, CWE-1021, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
 
@@ -125,6 +125,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 | Open redirect via unvalidated next parameter | [`open-redirect.py`](../vulns/python/open-redirect.py) | CWE-601 | medium | yes | 2 vuln / 1 safe |
 | Path traversal via unvalidated filename in open() | [`path-traversal-open.py`](../vulns/python/path-traversal-open.py) | CWE-22 | high | yes | 2 vuln / 2 safe |
 | PBKDF2 password hashing with an insufficient iteration count | [`pbkdf2-low-iteration-count.py`](../vulns/python/pbkdf2-low-iteration-count.py) | CWE-916 | high | yes | 1 vuln / 1 safe |
+| Permissive cross-origin policy with credentialed requests | [`permissive-cors-credentials.py`](../vulns/python/permissive-cors-credentials.py) | CWE-942 | medium | yes | 2 vuln / 1 safe |
 | Insecure deserialisation via pickle / yaml.load | [`pickle-deserialization.py`](../vulns/python/pickle-deserialization.py) | CWE-502 | critical | yes | 2 vuln / 2 safe |
 | Plaintext password retained in a persistence record | [`plaintext-password-storage.py`](../vulns/python/plaintext-password-storage.py) | CWE-256 | critical | yes | 1 vuln / 1 safe |
 | Proxy-shaped dict merges walk into __class__ / __proto__ | [`prototype-pollution-proxy.py`](../vulns/python/prototype-pollution-proxy.py) | CWE-1321 | high | yes | 2 vuln / 0 safe |

vulns/VULNERABILITY_CATALOG.json

@@ -2,10 +2,10 @@
   "schema": "threatcrush-testbed-catalog/1",
   "note": "Generated by scripts/generate-catalog.py \u2014 do not edit by hand.",
   "totals": {
-    "test_cases": 116,
-    "expected_detections": 116,
-    "vulnerable_markers": 215,
-    "safe_markers": 131,
+    "test_cases": 117,
+    "expected_detections": 117,
+    "vulnerable_markers": 217,
+    "safe_markers": 132,
     "languages": [
       "dotenv",
       "go",
@@ -2132,6 +2132,30 @@
         35
       ]
     },
+    {
+      "id": "py-permissive-cors-credentials",
+      "file": "vulns/python/permissive-cors-credentials.py",
+      "title": "Permissive cross-origin policy with credentialed requests",
+      "category": "python",
+      "language": "python",
+      "cwe": "CWE-942",
+      "cwes": [
+        "CWE-942"
+      ],
+      "severity": "medium",
+      "expected_detection": true,
+      "description": "The API accepts cookie-authenticated requests from any origin:",
+      "detection_target": "Flask/FastAPI response header writes where",
+      "safe_guard": "Both handlers are wrapped in `if False:` (unreachable dead code).",
+      "attribution": "line",
+      "vulnerable_lines": [
+        30,
+        40
+      ],
+      "safe_lines": [
+        55
+      ]
+    },
     {
       "id": "py-pickle-deserialization",
       "file": "vulns/python/pickle-deserialization.py",

vulns/python/permissive-cors-credentials.py

@@ -0,0 +1,59 @@
+"""
+@id py-permissive-cors-credentials
+@test-case Permissive cross-origin policy with credentialed requests
+@cwe CWE-942
+@severity medium
+@language python
+@expected-detection true
+@description The API accepts cookie-authenticated requests from any origin:
+             Access-Control-Allow-Origin is echoed from the request (or set to
+             `*`) while credentials are allowed. Any site the victim visits can
+             then issue authenticated reads and writes, since the browser will
+             attach the session cookies. The safe counterpart allows only a
+             fixed allow-listed origin. Detection target is the pairing of a
+             wildcard/reflected ACAO with allow-credentials, not the string
+             alone.
+@safe-guard Both handlers are wrapped in `if False:` (unreachable dead code).
+            Nothing is served over the network and no origin is contacted; the
+            allow-list origin is an unresolvable `.invalid` name.
+@detection-target Flask/FastAPI response header writes where
+                  Access-Control-Allow-Origin is `*` or request-reflected while
+                  Access-Control-Allow-Credentials is true on the same path.
+
+NEVER RUN IN PRODUCTION - intentional test case for scanner validation.
+"""
+
+
+def account_json_response(after_request, request_origin):
+    if False:
+        resp = after_request()
+        # VULNERABLE: CWE-942 - echoes any origin + allows cookies
+        resp.headers["Access-Control-Allow-Origin"] = request_origin
+        resp.headers["Access-Control-Allow-Credentials"] = "true"
+        return resp
+    return None
+
+
+def account_json_response_wildcard(after_request):
+    if False:
+        resp = after_request()
+        # VULNERABLE: CWE-942 - wildcard origin with credentials is rejected by
+        # browsers, but the code (and some proxies) treat it as permissive CORS
+        resp.headers["Access-Control-Allow-Origin"] = "*"
+        resp.headers["Access-Control-Allow-Credentials"] = "true"
+        return resp
+    return None
+
+
+def account_json_response_safe(after_request):
+    """Safe counterpart - the scanner should NOT flag this.
+
+    @expected-detection false
+    """
+    if False:
+        resp = after_request()
+        # SAFE: fixed allow-listed origin, credentials allowed only for it
+        resp.headers["Access-Control-Allow-Origin"] = "https://app.internal.invalid"
+        resp.headers["Access-Control-Allow-Credentials"] = "true"
+        return resp
+    return None