diff --git a/spec/overcommit/git_repo_spec.rb b/spec/overcommit/git_repo_spec.rb
index 128737c3..c4a64450 100644
--- a/spec/overcommit/git_repo_spec.rb
+++ b/spec/overcommit/git_repo_spec.rb
@@ -24,12 +24,12 @@
         end
 
         submodule = repo do
-          `git submodule add #{nested_submodule} nested-sub 2>&1 > #{File::NULL}`
+          `git -c protocol.file.allow=always submodule add #{nested_submodule} nested-sub 2>&1 > #{File::NULL}`
           `git commit -m "Add nested submodule"`
         end
 
         repo do
-          `git submodule add #{submodule} sub 2>&1 > #{File::NULL}`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub 2>&1 > #{File::NULL}`
           example.run
         end
       end
@@ -150,7 +150,7 @@
         end
 
         before do
-          `git submodule add #{submodule} sub 2>&1 > #{File::NULL}`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub 2>&1 > #{File::NULL}`
         end
 
         it { should_not include File.expand_path('sub') }
@@ -178,7 +178,7 @@
           `git commit --allow-empty -m "Submodule commit"`
         end
 
-        `git submodule add #{submodule} #{submodule_dir} 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{submodule} #{submodule_dir} 2>&1 > #{File::NULL}`
         `git commit -m "Add submodule"`
       end
 
@@ -282,7 +282,7 @@
         touch 'tracked'
         `git add tracked`
         `git commit -m "Initial commit"`
-        `git submodule add #{submodule} sub 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{submodule} sub 2>&1 > #{File::NULL}`
         touch 'staged'
         `git add staged`
         example.run
@@ -327,7 +327,7 @@
       end
 
       repo do
-        `git submodule add #{submodule} sub-repo 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{submodule} sub-repo 2>&1 > #{File::NULL}`
         `git commit -m "Initial commit"`
         example.run
       end
@@ -343,7 +343,7 @@
           `git commit --allow-empty -m "Another submodule"`
         end
 
-        `git submodule add #{another_submodule} another-sub-repo 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{another_submodule} another-sub-repo 2>&1 > #{File::NULL}`
       end
 
       it { should be_empty }
@@ -369,7 +369,7 @@
           `git commit --allow-empty -m "Another submodule"`
         end
 
-        `git submodule add #{another_submodule} yet-another-sub-repo 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{another_submodule} yet-another-sub-repo 2>&1 > #{File::NULL}`
         `git commit -m "Add yet another submodule"`
         `git rm sub-repo`
         `git rm yet-another-sub-repo`
diff --git a/spec/overcommit/hook_context/commit_msg_spec.rb b/spec/overcommit/hook_context/commit_msg_spec.rb
index 2aa68516..058f1508 100644
--- a/spec/overcommit/hook_context/commit_msg_spec.rb
+++ b/spec/overcommit/hook_context/commit_msg_spec.rb
@@ -298,7 +298,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           echo('Hello World', 'sub/submodule-file')
           `git submodule foreach "git add submodule-file" < #{File::NULL}`
@@ -474,7 +474,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           echo('Hello World', 'sub/submodule-file')
           `git submodule foreach "git add submodule-file" < #{File::NULL}`
@@ -500,7 +500,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           echo('Hello World', 'sub/submodule-file')
           `git submodule foreach "git add submodule-file" < #{File::NULL}`
@@ -532,7 +532,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           `git rm sub`
           example.run
@@ -561,7 +561,7 @@
       end
 
       repo do
-        `git submodule add #{submodule} test-sub 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{submodule} test-sub 2>&1 > #{File::NULL}`
         expect(subject).to_not include File.expand_path('test-sub')
       end
     end
diff --git a/spec/overcommit/hook_context/pre_commit_spec.rb b/spec/overcommit/hook_context/pre_commit_spec.rb
index dae42e66..719982a1 100644
--- a/spec/overcommit/hook_context/pre_commit_spec.rb
+++ b/spec/overcommit/hook_context/pre_commit_spec.rb
@@ -207,7 +207,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           echo('Hello World', 'sub/submodule-file')
           `git submodule foreach "git add submodule-file" < #{File::NULL}`
@@ -383,7 +383,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           echo('Hello World', 'sub/submodule-file')
           `git submodule foreach "git add submodule-file" < #{File::NULL}`
@@ -409,7 +409,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           echo('Hello World', 'sub/submodule-file')
           `git submodule foreach "git add submodule-file" < #{File::NULL}`
@@ -441,7 +441,7 @@
         end
 
         repo do
-          `git submodule add #{submodule} sub > #{File::NULL} 2>&1`
+          `git -c protocol.file.allow=always submodule add #{submodule} sub > #{File::NULL} 2>&1`
           `git commit -m "Add submodule"`
           `git rm sub`
           example.run
@@ -470,7 +470,7 @@
       end
 
       repo do
-        `git submodule add #{submodule} test-sub 2>&1 > #{File::NULL}`
+        `git -c protocol.file.allow=always submodule add #{submodule} test-sub 2>&1 > #{File::NULL}`
         expect(subject).to_not include File.expand_path('test-sub')
       end
     end
diff --git a/spec/overcommit/installer_spec.rb b/spec/overcommit/installer_spec.rb
index c7cfb05e..5283b2b6 100644
--- a/spec/overcommit/installer_spec.rb
+++ b/spec/overcommit/installer_spec.rb
@@ -231,8 +231,8 @@ def hook_files_installed?(hooks_dir)
       context 'which has an external git dir' do
         let(:submodule) { File.join(target, 'submodule') }
         before do
-          system 'git', 'submodule', 'add', target, 'submodule',
-                 chdir: target, out: :close, err: :close
+          system 'git', '-c', 'protocol.file.allow=always', 'submodule', 'add', target,
+                 'submodule', chdir: target, out: :close, err: :close
         end
         let(:submodule_git_file) { File.join(submodule, '.git') }
         let(:submodule_git_dir) do