For those who just want to quickly patch their 'old' Vagrant 1.0.x installations until they can upgrade to hashicorp/vagrant#1785

patch-insecure-defaults-vagrant-1.0.7.patch

From 021dc42756dc44e17d3b2555b0652b96dea39559 Mon Sep 17 00:00:00 2001
From: Sebastian Schulze <github.com(at)bascht.com>
Date: Wed, 19 Jun 2013 10:05:08 +0200
Subject: [PATCH] Quickly patch Vagrants insecure VirtualBox defaults [GH-1785]

---
 lib/vagrant/driver/virtualbox_4_0.rb | 2 +-
 lib/vagrant/driver/virtualbox_4_1.rb | 2 +-
 lib/vagrant/driver/virtualbox_4_2.rb | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/vagrant/driver/virtualbox_4_0.rb b/lib/vagrant/driver/virtualbox_4_0.rb
index b4e6b7e..4a5bdc6 100644
--- a/lib/vagrant/driver/virtualbox_4_0.rb
+++ b/lib/vagrant/driver/virtualbox_4_0.rb
@@ -137,7 +137,7 @@ module Vagrant
         ports.each do |options|
           pf_builder = [options[:name],
                         options[:protocol] || "tcp",
-                        "",
+                        "127.0.0.1",
                         options[:hostport],
                         "",
                         options[:guestport]]
diff --git a/lib/vagrant/driver/virtualbox_4_1.rb b/lib/vagrant/driver/virtualbox_4_1.rb
index 45e2d5a..fccf38e 100644
--- a/lib/vagrant/driver/virtualbox_4_1.rb
+++ b/lib/vagrant/driver/virtualbox_4_1.rb
@@ -137,7 +137,7 @@ module Vagrant
         ports.each do |options|
           pf_builder = [options[:name],
                         options[:protocol] || "tcp",
-                        "",
+                        "127.0.0.1",
                         options[:hostport],
                         "",
                         options[:guestport]]
diff --git a/lib/vagrant/driver/virtualbox_4_2.rb b/lib/vagrant/driver/virtualbox_4_2.rb
index 2eef773..88539bd 100644
--- a/lib/vagrant/driver/virtualbox_4_2.rb
+++ b/lib/vagrant/driver/virtualbox_4_2.rb
@@ -160,7 +160,7 @@ module Vagrant
         ports.each do |options|
           pf_builder = [options[:name],
                         options[:protocol] || "tcp",
-                        "",
+                        "127.0.0.1",
                         options[:hostport],
                         "",
                         options[:guestport]]
-- 
1.8.1.4