Fix unknown BeaconSetting names

In dissect.cstruct v4 unknown enum names becomes None, an extra check is done to ensure it has a proper name.

dissect/cobaltstrike/beacon.py

@@ -794,7 +794,7 @@ def settings_map(self, index_type="enum", pretty=False, parse=True) -> MappingPr
         for setting in self.settings_tuple:
             val = setting.value
             if index_type == "name":
-                key = setting.index.name
+                key = setting.index.name or str(setting.index)
             elif index_type == "const":
                 key = setting.index.value
             else:

tests/test_beacon.py

@@ -311,3 +311,15 @@ def test_beacon_domains_punycode(punycode_beacon_file):
     assert bconfig.domains == ["kçi.com"]
     assert bconfig.domains[0].encode("idna") == b"xn--ki-4ia.com"
     assert b"k\xe7i.com" in bconfig.raw_settings["SETTING_DOMAINS"]
+
+
+def test_beacon_setting_unknown_enum():
+    setting = (
+        beacon.cs_struct.uint16(6969).dumps(),
+        beacon.SettingsType.TYPE_PTR.dumps(),
+        beacon.cs_struct.uint16(3).dumps(),
+        b"foo",
+    )
+    config = beacon.BeaconConfig(b"".join(setting))
+    assert None not in config.settings
+    assert dict(config.settings) == {"BeaconSetting.6969": b"foo"}