fix: handle missing x_mitre_data_source_ref in data components

Author: elucchesileon

mitreattack/attackToExcel/stixToDf.py

@@ -290,7 +290,8 @@ def datasourcesToDf(src):
             if "x_mitre_aliases" in data_object:
                 row["aliases"] = ", ".join(sorted(data_object["x_mitre_aliases"][1:]))
             if data_object["type"] == "x-mitre-data-component":
-                row["name"] = f"{source_lookup[data_object['x_mitre_data_source_ref']]}: {data_object['name']}"
+                if "x_mitre_data_source_ref" in data_object:
+                    row["name"] = f"{source_lookup[data_object['x_mitre_data_source_ref']]}: {data_object['name']}"
                 row["type"] = "datacomponent"
             else:
                 row["type"] = "datasource"