diff --git a/bundler/spec/support/hax.rb b/bundler/spec/support/hax.rb
index c7fe3637cc5e..d46592b4bacc 100644
--- a/bundler/spec/support/hax.rb
+++ b/bundler/spec/support/hax.rb
@@ -50,4 +50,11 @@ class << self
       end
     end
   end
+
+  class Specification < BasicSpecification
+    if defined?(DEFAULT_GEMS_LIST)
+      remove_const :DEFAULT_GEMS_LIST
+      DEFAULT_GEMS_LIST = %w[irb json foo bar].freeze
+    end
+  end
 end
diff --git a/lib/rubygems/installer.rb b/lib/rubygems/installer.rb
index 0477b4703538..41d57bfb0ee5 100644
--- a/lib/rubygems/installer.rb
+++ b/lib/rubygems/installer.rb
@@ -321,14 +321,15 @@ def install
     dir_mode = options[:dir_mode]
     FileUtils.mkdir_p gem_dir, :mode => dir_mode && 0o755
 
+    extract_files
+
+    build_extensions
+    write_build_info_file
+
     if @options[:install_as_default]
       extract_bin
       write_default_spec
     else
-      extract_files
-
-      build_extensions
-      write_build_info_file
       run_post_build_hooks
     end
 
@@ -760,6 +761,12 @@ def verify_spec
     end
   end
 
+  def verify_default_gems
+    return unless options[:install_as_default]
+    return if Gem::Specification::DEFAULT_GEMS_LIST.include?(spec.name)
+    raise Gem::InstallError, "#{spec} is not a default gem."
+  end
+
   ##
   # Return the text for an application file.
 
@@ -925,6 +932,10 @@ def pre_install_checks
 
     ensure_loadable_spec
 
+    verify_spec
+
+    verify_default_gems
+
     if options[:install_as_default]
       Gem.ensure_default_gem_subdirectories gem_home
     else
diff --git a/lib/rubygems/specification.rb b/lib/rubygems/specification.rb
index 91d4408a16f4..f5b52f7259e8 100644
--- a/lib/rubygems/specification.rb
+++ b/lib/rubygems/specification.rb
@@ -110,6 +110,32 @@ class Gem::Specification < Gem::BasicSpecification
 
   VALID_NAME_PATTERN = /\A[a-zA-Z0-9\.\-\_]+\z/ # :nodoc:
 
+  DEFAULT_GEMS_LIST = %w[
+    bigdecimal
+    bundler
+    cmath
+    csv
+    date
+    dbm
+    etc
+    fcntl
+    fiddle
+    fileutils
+    gdbm
+    io-console
+    ipaddr
+    json
+    openssl
+    psych
+    rdoc
+    scanf
+    sdbm
+    stringio
+    strscan
+    webrick
+    zlib
+  ].freeze # :nodoc:
+
   # :startdoc:
 
   ##
diff --git a/test/rubygems/helper.rb b/test/rubygems/helper.rb
index 705ed71f0c82..9c8a4fb0bc93 100644
--- a/test/rubygems/helper.rb
+++ b/test/rubygems/helper.rb
@@ -63,6 +63,11 @@ def self.specific_extra_args_hash=(value)
   end
 end
 
+class Gem::Specification < Gem::BasicSpecification
+  remove_const :DEFAULT_GEMS_LIST
+  DEFAULT_GEMS_LIST = %w[systemgem default bundler a b c z].freeze
+end
+
 ##
 # RubyGemTestCase provides a variety of methods for testing rubygems and
 # gem-related behavior in a sandbox.  Through RubyGemTestCase you can install