Fix Quad9 analyzers crashes and add tests

api_app/analyzers_manager/observable_analyzers/dns/dns_malicious_detectors/quad9_malicious_detector.py

@@ -80,9 +80,13 @@ def _quad9_dns_query(self, observable) -> bool:
         dns_response = dns.message.from_wire(quad9_response.content)
         resolutions: list[str] = []
         for answer in dns_response.answer:
-            resolutions.extend([resolution.address for resolution in answer])
+            for record in answer:
+                if hasattr(record, "address"):
+                    resolutions.append(record.address)
+                elif hasattr(record, "target"):
+                    resolutions.append(str(record.target))
 
-        return bool(resolutions)
+        return bool(resolutions), resolutions
 
     def _google_dns_query(self, observable) -> bool:
         """Perform a DNS query with Google service, return True if Google answer the

api_app/analyzers_manager/observable_analyzers/dns/dns_resolvers/quad9_dns_resolver.py

@@ -45,10 +45,14 @@ def run(self):
             else:
                 quad9_response.raise_for_status()
 
-        json_response = quad9_response.json()
+        try:
+            json_response = quad9_response.json()
+        except Exception:
+            json_response = {}
         resolutions: list[str] = []
         for answer in json_response.get("Answer", []):
-            if "data" in answer:
-                resolutions.append(answer["data"])
+            data = answer.get("data")  # safe access
+            if data is not None:  # skip None values
+                resolutions.append(data)
 
         return dns_resolver_response(observable, resolutions)

tests/api_app/analyzers_manager/observable_analyzers/dns/test_quad9.py

@@ -0,0 +1,31 @@
+# This file is a part of IntelOwl https://github.com/intelowlproject/IntelOwl
+# See the file 'LICENSE' for copying permission.
+from unittest.mock import patch
+
+import pytest
+
+from api_app.analyzers_manager.observable_analyzers.dns import Quad9DNSResolver
+
+
+@pytest.mark.django_db
+@patch("httpx.Client.get")
+def test_quad9_dns_resolver_handles_non_utf8(mock_get):
+    class MockResponse:
+        content = b"\xd5\x00\x01"
+
+        @staticmethod
+        def raise_for_status():
+            pass
+
+        @staticmethod
+        def json():
+            return {"Answer": [{"data": "1.1.1.1"}]}
+
+    mock_get.return_value = MockResponse()
+
+    analyzer = Quad9DNSResolver(
+        observable_name="test.com", observable_classification="domain", config={}
+    )
+
+    result = analyzer.run()
+    assert "1.1.1.1" in result["resolutions"]