From bdc3adfde3d0abfd0ec14e3fdd12e2383843512d Mon Sep 17 00:00:00 2001
From: seonghobae <8172694+seonghobae@users.noreply.github.com>
Date: Mon, 10 Aug 2026 05:14:16 +0000
Subject: [PATCH] =?UTF-8?q?=F0=9F=9B=A1=EF=B8=8F=20Sentinel:=20[HIGH]=20Fi?=
 =?UTF-8?q?x=20AttributeError=20in=20URL=20parsing?=
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🚨 Severity: HIGH
💡 Vulnerability: `_is_safe_url` 함수에 문자열이 아닌 값(True, None, 123 등)이 전달될 경우 `urllib.parse.urlparse`에서 `AttributeError` 예외가 발생하여 애플리케이션 충돌 및 API 500 에러를 유발할 수 있습니다.
🎯 Impact: 잘못된 입력 값으로 인한 프로세스 비정상 종료 및 서비스 가용성 저하 (Denial of Service).
🔧 Fix: URL 문자열 파싱 전 `isinstance(url, str)` 체크를 추가하여, 문자열이 아닌 입력값에 대해서는 안전하게 `False`를 반환(Fail Closed)하도록 수정했습니다.
✅ Verification: `pytest tests/test_ssrf_protection.py`를 통해 문자열 외 타입에 대해 올바르게 실패하는지 검증 완료.
---
 .jules/sentinel.md                | 4 ++++
 appguardrail_core/controlplane.py | 3 +++
 scanner/cli/appguardrail.py       | 3 +++
 tests/test_ssrf_protection.py     | 8 ++++++++
 4 files changed, 18 insertions(+)

diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index f3e9114a..7eb6065b 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -122,3 +122,7 @@
 **Vulnerability:** DOM XSS via unescaped `severity` string interpolated into `innerHTML` in `scanner/dashboard/index.html`.
 **Learning:** Even enum-like or seemingly safe meta-fields like `severity` can contain malicious payloads if sourced from user input (findings file) and directly injected into innerHTML.
 **Prevention:** Always use the `esc()` sanitizer for any dynamically rendered property from `findings.json`, regardless of expected schema types.
+## 2026-08-05 - Missing Type Validation for URL Parsers
+**Vulnerability:** Core URL validation functions like `_is_safe_url` used `urllib.parse.urlparse` without first ensuring the input was a string. Passing boolean, integer, or `None` types triggered an unhandled `AttributeError`, resulting in a brittle application or API 500 errors instead of securely failing closed.
+**Learning:** Functions that act as security boundaries must explicitly validate input types, particularly when passing those inputs to stdlib parser functions that assume specific types and throw non-standard errors (like `AttributeError` instead of `ValueError`).
+**Prevention:** Always verify input types with `isinstance(url, str)` at the beginning of validation functions before passing them to parsing logic.
diff --git a/appguardrail_core/controlplane.py b/appguardrail_core/controlplane.py
index bf74784e..f086abe1 100644
--- a/appguardrail_core/controlplane.py
+++ b/appguardrail_core/controlplane.py
@@ -221,6 +221,9 @@ def _is_safe_url(url: str) -> bool:
     import urllib.parse
     import socket
 
+    if not isinstance(url, str):
+        return False
+
     try:
         parsed = urllib.parse.urlparse(
             url
diff --git a/scanner/cli/appguardrail.py b/scanner/cli/appguardrail.py
index c655195a..b8880429 100644
--- a/scanner/cli/appguardrail.py
+++ b/scanner/cli/appguardrail.py
@@ -1622,6 +1622,9 @@ def _is_safe_url(url: str) -> bool:
     import socket
     import urllib.parse
 
+    if not isinstance(url, str):
+        return False
+
     try:
         parsed = urllib.parse.urlparse(
             url
diff --git a/tests/test_ssrf_protection.py b/tests/test_ssrf_protection.py
index 3462f72f..0a584ac4 100644
--- a/tests/test_ssrf_protection.py
+++ b/tests/test_ssrf_protection.py
@@ -65,6 +65,14 @@ def test_is_safe_url_reserved_and_not_global_ips():
     assert not _is_safe_url("http://0.0.0.0/")
 
 
+def test_is_safe_url_non_string_inputs():
+    assert not _is_safe_url(True)
+    assert not _is_safe_url(False)
+    assert not _is_safe_url(123)
+    assert not _is_safe_url(None)
+    assert not _is_safe_url(["http://google.com"])
+
+
 def test_push_findings_unsafe_url_handled_properly(monkeypatch, capsys):
     from scanner.cli.appguardrail import _push_findings