diff --git a/lib/common_helper.rb b/lib/common_helper.rb
index 9bda916c..61744862 100644
--- a/lib/common_helper.rb
+++ b/lib/common_helper.rb
@@ -72,6 +72,14 @@ def get_equal_string_end(stringarray = [""])
   already_found
 end
 
+# Since ruby 1.9.2, URI::escape is obsolete
+# See http://rosettacode.org/wiki/URL_encoding#Ruby and http://www.ruby-forum.com/topic/207489
+module URI
+  def self.escape(str)
+    URI.encode_www_form_component(str).gsub("+", "%20")
+  end
+end
+
 if RUBY_VERSION < "1.9"
   class Array
     # Fix for grep with symbols in ruby <= 1.8.7
diff --git a/lib/wpscan/modules/malwares.rb b/lib/wpscan/modules/malwares.rb
index c3eeeaee..b190f7c2 100644
--- a/lib/wpscan/modules/malwares.rb
+++ b/lib/wpscan/modules/malwares.rb
@@ -26,7 +26,7 @@ module Malwares
 
   # return array of string (url of malwares found)
   def malwares(malwares_file_path = nil)
-    if @malwares.nil?
+    unless @malwares
       malwares_found = []
       malwares_file = Malwares.malwares_file(malwares_file_path)
       index_page_body = Browser.instance.get(@uri.to_s).body
diff --git a/lib/wpscan/wp_target.rb b/lib/wpscan/wp_target.rb
index 833d7810..1fbcd362 100644
--- a/lib/wpscan/wp_target.rb
+++ b/lib/wpscan/wp_target.rb
@@ -38,6 +38,7 @@ class WpTarget
     @verbose        = options[:verbose]
     @wp_content_dir = options[:wp_content_dir]
     @wp_plugins_dir = options[:wp_plugins_dir]
+    @multisite      = nil
 
     Browser.instance(options.merge(:max_threads => options[:threads]))
   end
diff --git a/lib/wpscan/wpscan_options.rb b/lib/wpscan/wpscan_options.rb
index 34942ca3..80f3eaf7 100644
--- a/lib/wpscan/wpscan_options.rb
+++ b/lib/wpscan/wpscan_options.rb
@@ -45,7 +45,9 @@ class WpscanOptions
   attr_accessor *ACCESSOR_OPTIONS
 
   def initialize
-
+    ACCESSOR_OPTIONS.each do |option|
+      instance_variable_set("@#{option}", nil)
+    end
   end
 
   def url=(url)