test: add zip-slip-traversal fixture (CWE-409)

docs/VULNERABILITY_CATALOG.md

@@ -7,12 +7,12 @@ from each file's header comment, so this page cannot drift from the source.
 
 ## Totals
 
-- **Test cases:** 122
-- **Expected detections:** 122
-- **`VULNERABLE:` markers:** 227 (individual lines a scanner should flag)
-- **`SAFE:` markers:** 138 (lines a scanner must not flag — the false-positive control group)
+- **Test cases:** 124
+- **Expected detections:** 124
+- **`VULNERABLE:` markers:** 231 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 141 (lines a scanner must not flag — the false-positive control group)
 - **Languages:** 8 — dotenv, go, java, javascript, json, python, ruby, text
-- **CWE categories:** 86 — 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-311, 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-522, 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
+- **CWE categories:** 87 — 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-311, 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-409, 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-522, 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
 
 ## How coverage is scored
 
@@ -152,6 +152,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 | XPath injection via string interpolation | [`xpath-injection.py`](../vulns/python/xpath-injection.py) | CWE-643 | high | yes | 1 vuln / 1 safe |
 | XSS via Jinja2 autoescape disabled and server-side template injection | [`xss-jinja2-autoescape-off.py`](../vulns/python/xss-jinja2-autoescape-off.py) | CWE-79 | high | yes | 3 vuln / 1 safe |
 | XML external entity expansion in an insecure parser | [`xxe-lxml-resolve.py`](../vulns/python/xxe-lxml-resolve.py) | CWE-611 | high | yes | 2 vuln / 1 safe |
+| Path traversal through zip archive entry names (Zip Slip) | [`zip-slip-traversal.py`](../vulns/python/zip-slip-traversal.py) | CWE-409 | high | yes | 2 vuln / 1 safe |
 
 ## Ruby
 

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": 122,
-    "expected_detections": 122,
-    "vulnerable_markers": 227,
-    "safe_markers": 138,
+    "test_cases": 124,
+    "expected_detections": 124,
+    "vulnerable_markers": 231,
+    "safe_markers": 141,
     "languages": [
       "dotenv",
       "go",
@@ -65,6 +65,7 @@
       "CWE-377",
       "CWE-384",
       "CWE-400",
+      "CWE-409",
       "CWE-434",
       "CWE-441",
       "CWE-460",
@@ -2772,6 +2773,30 @@
         42
       ]
     },
+    {
+      "id": "py-zip-slip-traversal",
+      "file": "vulns/python/zip-slip-traversal.py",
+      "title": "Path traversal through zip archive entry names (Zip Slip)",
+      "category": "python",
+      "language": "python",
+      "cwe": "CWE-409",
+      "cwes": [
+        "CWE-409"
+      ],
+      "severity": "high",
+      "expected_detection": true,
+      "description": "A zip archive from an untrusted source is extracted without",
+      "detection_target": "zipfile.ZipFile.extractall / extract / namelist-derived",
+      "safe_guard": "All extraction wrapped in `if False:` (unreachable dead code).",
+      "attribution": "line",
+      "vulnerable_lines": [
+        32,
+        40
+      ],
+      "safe_lines": [
+        52
+      ]
+    },
     {
       "id": "rb-cwe480-credential-comparison",
       "file": "vulns/ruby/cwe-480-ruby.rb",

vulns/python/zip-slip-traversal.py

@@ -0,0 +1,60 @@
+"""
+@id py-zip-slip-traversal
+@test-case Path traversal through zip archive entry names (Zip Slip)
+@cwe CWE-409
+@severity high
+@language python
+@expected-detection true
+@description A zip archive from an untrusted source is extracted without
+             checking that each member name stays inside the destination
+             directory. An entry named `../../etc/cron.d/backdoor` escapes the
+             target dir, letting the attacker write arbitrary files on the
+             host. The safe counterpart validates every member against the
+             resolved destination root. Detection target is an extract call
+             where entry names are used for write paths with no containment
+             check.
+@safe-guard All extraction wrapped in `if False:` (unreachable dead code).
+            No archive is read from disk; the ZipFile is built from a
+            synthetic bytes literal.
+@detection-target zipfile.ZipFile.extractall / extract / namelist-derived
+                  writes where ZipInfo.filename is not checked for
+                  ../ or absolute-path traversal before being resolved.
+
+NEVER RUN IN PRODUCTION - intentional test case for scanner validation.
+"""
+
+import zipfile
+import io
+
+
+def extract_zip_slip(zip_bytes: bytes, dest: str) -> None:
+    if False:
+        # VULNERABLE: CWE-409 - entry names trusted, no containment check
+        with zipfile.ZipFile(io.BytesIO(zip_bytes)) as zf:
+            zf.extractall(dest)
+    return None
+
+
+def extract_zip_slip_single(zip_bytes: bytes, dest: str, member: str) -> None:
+    if False:
+        # VULNERABLE: CWE-409 - single member, still no traversal check
+        with zipfile.ZipFile(io.BytesIO(zip_bytes)) as zf:
+            zf.extract(member, dest)
+    return None
+
+
+def extract_zip_safe(zip_bytes: bytes, dest: str) -> None:
+    """Safe counterpart - the scanner should NOT flag this.
+
+    @expected-detection false
+    """
+    if False:
+        # SAFE: validate each member stays within the destination root
+        with zipfile.ZipFile(io.BytesIO(zip_bytes)) as zf:
+            for info in zf.infolist():
+                import os
+                target = os.path.realpath(os.path.join(dest, info.filename))
+                if not target.startswith(os.path.realpath(dest) + os.sep):
+                    raise ValueError("member escapes destination: " + info.filename)
+            zf.extractall(dest)
+    return None