diff --git a/.github/workflows/latest-npm.yml b/.github/workflows/latest-npm.yml
index b616158..b66c605 100644
--- a/.github/workflows/latest-npm.yml
+++ b/.github/workflows/latest-npm.yml
@@ -8,6 +8,12 @@ jobs:
     outputs:
       latest: ${{ steps.set-matrix.outputs.requireds }}
     steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            iojs.org:443
+            nodejs.org:443
       - uses: ljharb/actions/node/matrix@main
         id: set-matrix
         with:
@@ -39,6 +45,14 @@ jobs:
           - node-version: "0.10"
 
     steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            github.com:443
+            iojs.org:443
+            nodejs.org:443
+            registry.npmjs.org:443
       - uses: actions/checkout@v2
       - uses: ljharb/actions/node/install@main
         name: 'nvm install-latest-npm'
@@ -55,4 +69,8 @@ jobs:
     needs: [nodes]
     runs-on: ubuntu-latest
     steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@v1
+        with:
+          egress-policy: block
       - run: 'echo tests completed'
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 32f279d..62fc960 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -8,6 +8,12 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
+      - uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            github.com:443
+            nodejs.org:443
+            registry.npmjs.org:443
       - uses: actions/checkout@v2
       - uses: ljharb/actions/node/install@main
         name: 'nvm install ${{ matrix.node-version }} && npm install'
@@ -20,6 +26,14 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
+      - uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            ghcr.io:443
+            github.com:443
+            pkg-containers.githubusercontent.com:443
+            nodejs.org:443
+            registry.npmjs.org:443
       - uses: actions/checkout@v2
       - uses: ljharb/actions/node/install@main
         name: 'nvm install ${{ matrix.node-version }} && npm install'
@@ -32,6 +46,12 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
+      - uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            github.com:443
+            nodejs.org:443
+            registry.npmjs.org:443
       - uses: actions/checkout@v2
       - uses: ljharb/actions/node/install@main
         name: 'nvm install ${{ matrix.node-version }} && npm install'
@@ -44,6 +64,10 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
+      - uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            github.com:443
       - uses: actions/checkout@v2
       - name: check tests filenames
         run: ./rename_test.sh --check
diff --git a/.github/workflows/rebase.yml b/.github/workflows/rebase.yml
index e97e6a9..9f48710 100644
--- a/.github/workflows/rebase.yml
+++ b/.github/workflows/rebase.yml
@@ -11,6 +11,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+    - name: Harden Runner
+      uses: step-security/harden-runner@v1
+      with:
+        allowed-endpoints:
+          api.github.com:443
+          github.com:443
     - uses: actions/checkout@v2
     - uses: ljharb/rebase@master
       env:
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index dfd9969..52c133d 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -8,6 +8,12 @@ jobs:
       contents: read
     runs-on: ubuntu-latest
     steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            github.com:443
+            registry.npmjs.org:443
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v2
         with:
diff --git a/.github/workflows/require-allow-edits.yml b/.github/workflows/require-allow-edits.yml
index b92dcd5..427eecb 100644
--- a/.github/workflows/require-allow-edits.yml
+++ b/.github/workflows/require-allow-edits.yml
@@ -11,6 +11,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+    - name: Harden Runner
+      uses: step-security/harden-runner@v1
+      with:
+        allowed-endpoints:
+          api.github.com:443
     - uses: ljharb/require-allow-edits@main
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/shellcheck.yml b/.github/workflows/shellcheck.yml
index 7b375a8..aafcb7f 100644
--- a/.github/workflows/shellcheck.yml
+++ b/.github/workflows/shellcheck.yml
@@ -26,9 +26,18 @@ jobs:
             file: nvm-exec # only runs in bash
 
     steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@v1
+        with:
+          allowed-endpoints:
+            ghcr.io:443
+            github.com:443
+            pkg-containers.githubusercontent.com:443
       - uses: actions/checkout@v2
       - name: Install shellcheck
         run: brew install shellcheck
+        env:
+          HOMEBREW_NO_ANALYTICS: 1
       - run: "shellcheck --version"
       - name: Run shellcheck on ${{ matrix.file }}
         run: shellcheck -s ${{ matrix.shell }} ${{ matrix.file }}
@@ -39,4 +48,8 @@ jobs:
       needs: [shellcheck_matrix]
       runs-on: ubuntu-latest
       steps:
+        - name: Harden Runner
+          uses: step-security/harden-runner@v1
+          with:
+            egress-policy: block
         - run: 'echo tests completed'
diff --git a/.github/workflows/toc.yml b/.github/workflows/toc.yml
index 60ed577..6a0fa6d 100644
--- a/.github/workflows/toc.yml
+++ b/.github/workflows/toc.yml
@@ -11,6 +11,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+    - name: Harden Runner
+      uses: step-security/harden-runner@v1
+      with:
+        allowed-endpoints:
+          github.com:443
+          registry.npmjs.org:443
     - uses: actions/checkout@v2
       with:
         # https://github.com/actions/checkout/issues/217#issue-599945005