diff --git a/.github/workflows/cron_ci.yml b/.github/workflows/cron_ci.yml
index be54fb40..052ed5ed 100644
--- a/.github/workflows/cron_ci.yml
+++ b/.github/workflows/cron_ci.yml
@@ -4,6 +4,9 @@ on:
   schedule:
     - cron:  '0 0 * * 0'
 
+permissions:
+  contents: read
+
 jobs:
   interop-tests:
     runs-on: ubuntu-latest
@@ -11,6 +14,12 @@ jobs:
     container:
       image: elixir:1.9
     steps:
+    - name: Harden the runner
+      uses: step-security/harden-runner@9af89fc71515a100421586dfdb3dc9c984fbf411 # v2
+      with:
+        use-policy-store: true
+        api-key: ${{ secrets.GH_FRESHAENGINEERING_STEP_SECURITY_API_KEY }}
+
     - uses: actions/checkout@50fbc622fc4ef5163becd7fab6573eac35f8462e # v1
     - name: Install Dependencies
       run: |