diff --git a/actionpack-cloudfront.gemspec b/actionpack-cloudfront.gemspec
index c95355c..ca6449d 100644
--- a/actionpack-cloudfront.gemspec
+++ b/actionpack-cloudfront.gemspec
@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
   spec.add_runtime_dependency     'actionpack', '>= 4.2'
   spec.add_runtime_dependency     'railties', '>= 4.2'
+  spec.add_runtime_dependency     'json', '>= 2.4.0'
   spec.add_development_dependency 'appraisal'
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'
diff --git a/lib/action_pack/cloudfront/ip_ranges.rb b/lib/action_pack/cloudfront/ip_ranges.rb
index d9bb1a7..e11574d 100644
--- a/lib/action_pack/cloudfront/ip_ranges.rb
+++ b/lib/action_pack/cloudfront/ip_ranges.rb
@@ -43,11 +43,11 @@ def ip_data
         Timeout.timeout(5) do
           uri = URI('https://ip-ranges.amazonaws.com/ip-ranges.json')
           res = Net::HTTP.get(uri)
-          JSON.parse(res)
+          JSON.parse(res, freeze: true)
         end
       rescue
         backup_json = File.join File.dirname(__FILE__), 'ip-ranges.json'
-        JSON.parse File.read(backup_json)
+        JSON.load_file(backup_json, freeze: true)
       end
 
       extend self