Add CWE-208 HMAC timing comparison test case

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:** 62
-- **Expected detections:** 62
-- **`VULNERABLE:` markers:** 123 (individual lines a scanner should flag)
-- **`SAFE:` markers:** 73 (lines a scanner must not flag — the false-positive control group)
+- **Test cases:** 63
+- **Expected detections:** 63
+- **`VULNERABLE:` markers:** 124 (individual lines a scanner should flag)
+- **`SAFE:` markers:** 74 (lines a scanner must not flag — the false-positive control group)
 - **Languages:** 8 — dotenv, go, java, javascript, json, python, ruby, text
-- **CWE categories:** 46 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-95, CWE-113, CWE-117, CWE-190, CWE-201, CWE-209, CWE-256, CWE-295, CWE-321, CWE-327, CWE-330, CWE-338, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-489, CWE-502, CWE-506, CWE-532, CWE-601, CWE-611, CWE-614, CWE-639, CWE-643, CWE-681, CWE-759, CWE-798, CWE-862, CWE-915, CWE-918, CWE-942, CWE-943, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
+- **CWE categories:** 47 — CWE-20, CWE-22, CWE-78, CWE-79, CWE-89, CWE-90, CWE-95, CWE-113, CWE-117, CWE-190, CWE-201, CWE-208, CWE-209, CWE-256, CWE-295, CWE-321, CWE-327, CWE-330, CWE-338, CWE-346, CWE-347, CWE-352, CWE-362, CWE-377, CWE-384, CWE-489, CWE-502, CWE-506, CWE-532, CWE-601, CWE-611, CWE-614, CWE-639, CWE-643, CWE-681, CWE-759, CWE-798, CWE-862, CWE-915, CWE-918, CWE-942, CWE-943, CWE-1236, CWE-1321, CWE-1333, CWE-1336, CWE-1357
 
 ## How coverage is scored
 
@@ -48,6 +48,7 @@ counts as a detection. See `docs/SCANNER_INTEGRATION.md`.
 | Credentialed CORS configured with a wildcard origin | [`cors-wildcard-credentials.js`](../vulns/javascript/cors-wildcard-credentials.js) | CWE-942 | high | yes | 1 vuln / 1 safe |
 | CSRF via missing anti-CSRF token on state-changing POST | [`csrf-missing-token.js`](../vulns/javascript/csrf-missing-token.js) | CWE-352 | high | yes | 3 vuln / 1 safe |
 | Hardcoded cryptographic key used for application encryption | [`hardcoded-crypto-key.js`](../vulns/javascript/hardcoded-crypto-key.js) | CWE-321 | high | yes | 1 vuln / 1 safe |
+| Timing-unsafe comparison of an HMAC webhook signature | [`hmac-timing-unsafe-compare.js`](../vulns/javascript/hmac-timing-unsafe-compare.js) | CWE-208 | medium | yes | 1 vuln / 1 safe |
 | Password-reset URL poisoning via untrusted Host header | [`host-header-password-reset.js`](../vulns/javascript/host-header-password-reset.js) | CWE-346 | high | yes | 1 vuln / 1 safe |
 | HTTP response splitting via unsanitized header value | [`http-header-injection.js`](../vulns/javascript/http-header-injection.js) | CWE-113 | high | yes | 1 vuln / 1 safe |
 | IDOR via unscoped object lookup | [`idor-unscoped-object-lookup.js`](../vulns/javascript/idor-unscoped-object-lookup.js) | CWE-639 | high | yes | 1 vuln / 1 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": 62,
-    "expected_detections": 62,
-    "vulnerable_markers": 123,
-    "safe_markers": 73,
+    "test_cases": 63,
+    "expected_detections": 63,
+    "vulnerable_markers": 124,
+    "safe_markers": 74,
     "languages": [
       "dotenv",
       "go",
@@ -37,6 +37,7 @@
       "CWE-117",
       "CWE-190",
       "CWE-201",
+      "CWE-208",
       "CWE-209",
       "CWE-256",
       "CWE-295",
@@ -367,6 +368,29 @@
         30
       ]
     },
+    {
+      "id": "js-hmac-timing-unsafe-compare",
+      "file": "vulns/javascript/hmac-timing-unsafe-compare.js",
+      "title": "Timing-unsafe comparison of an HMAC webhook signature",
+      "category": "javascript",
+      "language": "javascript",
+      "cwe": "CWE-208",
+      "cwes": [
+        "CWE-208"
+      ],
+      "severity": "medium",
+      "expected_detection": true,
+      "description": "A computed HMAC is compared to an attacker-supplied signature",
+      "detection_target": "A secret-derived HMAC digest compared to untrusted input",
+      "safe_guard": "Both examples are behind if (false), receive only caller-supplied",
+      "attribution": "line",
+      "vulnerable_lines": [
+        24
+      ],
+      "safe_lines": [
+        35
+      ]
+    },
     {
       "id": "js-host-header-password-reset",
       "file": "vulns/javascript/host-header-password-reset.js",

vulns/javascript/hmac-timing-unsafe-compare.js

@@ -0,0 +1,39 @@
+/**
+ * @id js-hmac-timing-unsafe-compare
+ * @test-case Timing-unsafe comparison of an HMAC webhook signature
+ * @cwe CWE-208
+ * @severity medium
+ * @language javascript
+ * @expected-detection true
+ * @description A computed HMAC is compared to an attacker-supplied signature
+ *              with ordinary string equality, which can return after the first
+ *              mismatch and expose prefix information through response timing.
+ * @safe-guard Both examples are behind if (false), receive only caller-supplied
+ *             values, perform no I/O, and cannot execute or contact a service.
+ * @detection-target A secret-derived HMAC digest compared to untrusted input
+ *                   with === instead of a constant-time comparison primitive.
+ */
+
+'use strict';
+
+const crypto = require('crypto');
+
+function verifyWebhookVulnerable(body, suppliedSignature, secret) {
+  if (false) {
+    const expectedSignature = crypto.createHmac('sha256', secret).update(body).digest('hex');
+    return expectedSignature === suppliedSignature; // VULNERABLE: CWE-208 timing-unsafe MAC comparison
+  }
+}
+
+/** Safe counterpart. @expected-detection false */
+function verifyWebhookSafe(body, suppliedSignature, secret) {
+  if (false) {
+    const expectedSignature = crypto.createHmac('sha256', secret).update(body).digest();
+    const candidateSignature = Buffer.from(suppliedSignature, 'hex');
+
+    return candidateSignature.length === expectedSignature.length
+      && crypto.timingSafeEqual(expectedSignature, candidateSignature); // SAFE: equal-length buffers compared in constant time
+  }
+}
+
+module.exports = { verifyWebhookVulnerable, verifyWebhookSafe };