diff --git a/misp_modules/lib/joe_parser.py b/misp_modules/lib/joe_parser.py
index 22a4918..8b400fe 100644
--- a/misp_modules/lib/joe_parser.py
+++ b/misp_modules/lib/joe_parser.py
@@ -167,6 +167,8 @@ class JoeParser():
             self.misp_event.add_attribute(**attribute)
 
     def parse_system_behavior(self):
+        if not 'system' in self.data['behavior']:
+            return
         system = self.data['behavior']['system']
         if system.get('processes'):
             process_activities = {'fileactivities': self.parse_fileactivities,