Fix invalid IP address assignment in Windows network plugin

dissect/target/plugins/os/windows/network.py

@@ -244,9 +244,13 @@ def _get_config_value(key: RegistryKey, name: str, sep: str | None = None) -> se
 
 def _construct_interface(key: RegistryKey, ip_key: str, subnet_key: str) -> set[str]:
     interface = ""
+
     if ip := _get_config_value(key, ip_key):
         interface = next(iter(ip))
 
+    if not interface:
+        return set()
+
     if subnet := _get_config_value(key, subnet_key):
         interface = f"{interface}/{next(iter(subnet))}"
 

tests/plugins/os/windows/test_network.py

@@ -130,6 +130,20 @@ class MockRegVal:
             },
             id="OTHER empty",
         ),
+        pytest.param(
+            {
+                "NetCfgInstanceId": "TESTINGINSTANCEID",
+                "EnableDHCP": 1,
+                "DhcpIPAddress": "0.0.0.0",
+                "DhcpSubnetMask": "255.255.255.0",
+            },
+            {
+                "_NO_INTERFACES": True,
+                "enabled": True,
+                "cidr": {},  # and not {'/255.255.255.0'}
+            },
+            id="invalid cidr",
+        ),
     ],
 )
 def test_windows_network(
@@ -167,6 +181,11 @@ def test_windows_network(
         assert network.gateways() == expected_values.get("gateway", [])
         assert network.macs() == expected_values.get("mac", [])
 
+        if expected_values.get("_NO_INTERFACES"):
+            with pytest.raises(StopIteration):
+                next(iter(network.interfaces()))
+            return
+
         network_interface = next(iter(network.interfaces()))
         assert network_interface.name == expected_values.get("name")
         assert network_interface.type == expected_values.get("type")