🛡️ Sentinel: [HIGH] 빈 호스트명을 악용한 SSRF 우회 취약점 패치

.jules/sentinel.md

@@ -127,3 +127,8 @@
 **Vulnerability:** The `/api/v1/webhook` POST endpoint in `appguardrail_core/controlplane.py` failed to validate the `url` property when accepting it into the database, leading to Stored SSRF risks. In addition, the core SSRF validation logic (`_is_safe_url`) in both the CLI and control-plane did not verify the input type (e.g. `isinstance(url, str)`). Passing non-string types (like integers) resulted in unhandled `AttributeError` exceptions inside `urllib.parse.urlparse`, which led to API 500 crashes on malicious JSON payloads.
 **Learning:** Network endpoints must explicitly validate the data type of user-provided configurations prior to execution or storage. Furthermore, webhooks configured by users should always be checked for SSRF when saved, as trusting them later assumes input has already been safely validated, bypassing downstream network guardrails.
 **Prevention:** Apply `_is_safe_url` checks directly upon ingestion (e.g., in `/api/v1/webhook`) and enforce type checks `if not isinstance(url, str): return False` prior to using library parsing functions like `urlparse`. Always return gracefully failing responses (like `400 Bad Request`) for unsafe URLs instead of allowing unhandled 500 server errors.
+
+## 2026-07-29 - [SSRF Bypass with Empty Hostnames]
+**Vulnerability:** Server-Side Request Forgery (SSRF) bypass due to `urllib.parse.urlparse` returning an empty string for the hostname of malformed URLs (e.g., `http://` or `http://user@`). The subsequent host parsing logic resulted in an empty string being passed to `ipaddress.ip_address` and `socket.getaddrinfo`. These functions threw `ValueError` and `socket.gaierror` exceptions respectively, which were caught and ignored, leading the `_is_safe_url` function to incorrectly return `True`.
+**Learning:** `urllib.parse.urlparse` can produce empty strings for hostnames on certain malformed URLs. When this empty string is processed by underlying networking and IP resolution libraries, the resulting exceptions might be handled in a way that accidentally bypasses the security check.
+**Prevention:** Always explicitly check that a valid, non-empty hostname was successfully extracted by `urlparse` before attempting to validate the IP address or perform DNS resolution. Reject any URL that does not have a recognizable hostname.

appguardrail_core/controlplane.py

@@ -236,6 +236,8 @@ def _is_safe_url(url: str) -> bool:
         return False
 
     host = (parsed.hostname or "").lower()
+    if not host:
+        return False
     raw = host.split("%", 1)[0].strip("[]")
 
     def is_bad_ip(ip) -> bool:

scanner/cli/appguardrail.py

@@ -1648,6 +1648,8 @@ def _is_safe_url(url: str) -> bool:
         return False
 
     host = (parsed.hostname or "").lower()
+    if not host:
+        return False
     raw = host.split("%", 1)[0].strip("[]")
 
     def is_bad_ip(ip) -> bool: