diff --git a/tasks/setup.yml b/tasks/setup.yml
index 4ebac3b..f808334 100644
--- a/tasks/setup.yml
+++ b/tasks/setup.yml
@@ -44,7 +44,7 @@
         dest: "{{ prometheus_config_dir }}/prometheus.yml"
         owner: "{{ prometheus_user }}"
         group: "{{ prometheus_user }}"
-        mode: 0640
+        mode: 0600
         validate: "{{ prometheus_base_dir }}/promtool check config %s"
       notify: __prometheus_reload