diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index fd5a275c..82c99bb7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [ "master" ]
 
+permissions:
+  contents: read
+
 jobs:
   test_gem:
     runs-on: ubuntu-latest
@@ -14,10 +17,15 @@ jobs:
       fail-fast: false
 
     steps:
-      - uses: actions/checkout@v3
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
 
       - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@13e7a03dc3ac6c3798f4570bfead2aed4d96abfb # v1.244.0
         with:
           ruby-version: 2.7.6
           bundler-cache: true