diff --git a/lib/vagrant/util/downloader.rb b/lib/vagrant/util/downloader.rb
index a3ee5459e..edaf99e85 100644
--- a/lib/vagrant/util/downloader.rb
+++ b/lib/vagrant/util/downloader.rb
@@ -14,7 +14,9 @@ module Vagrant
     class Downloader
       # Custom user agent provided to cURL so that requests to URL shorteners
       # are properly tracked.
-      USER_AGENT = "Vagrant/#{VERSION}"
+      #
+      #     Vagrant/1.7.4 (+https://www.vagrantup.com; ruby2.1.0)
+      USER_AGENT = "Vagrant/#{VERSION} (+https://www.vagrantup.com; #{RUBY_ENGINE}#{RUBY_VERSION})".freeze
 
       attr_reader :source
       attr_reader :destination