diff --git a/lib/rex/exploitation/jsobfu.rb b/lib/rex/exploitation/jsobfu.rb
index cb437ab468..8b2c4ad12f 100644
--- a/lib/rex/exploitation/jsobfu.rb
+++ b/lib/rex/exploitation/jsobfu.rb
@@ -1,6 +1,7 @@
 # -*- coding: binary -*-
 
 require 'rex/text'
+require 'rex/random_identifier_generator'
 require 'rkelly'
 
 module Rex
@@ -69,6 +70,11 @@ class JSObfu
     @funcs = {}
     @vars  = {}
     @debug = false
+    @rand_gen = Rex::RandomIdentifierGenerator.new(
+      :max_length => 15,
+      :first_char_set => Rex::Text::Alpha+"_$",
+      :char_set => Rex::Text::AlphaNumeric+"_$",
+    )
   end
 
   #
@@ -119,7 +125,7 @@ class JSObfu
   # @return [String] a unique random var name that is not a reserved keyword
   def random_var_name
     loop do
-      text = Rex::Text.rand_text_alpha(3+rand(12))
+      text = random_string
       unless @vars.has_value?(text) or RESERVED_KEYWORDS.include?(text)
         return text
       end
@@ -128,6 +134,11 @@ class JSObfu
 
 protected
 
+  # @return [String] a random string
+  def random_string
+    @rand_gen.generate
+  end
+
   #
   # Recursive method to obfuscate the given +ast+.
   #
diff --git a/spec/lib/rex/exploitation/jsobfu_spec.rb b/spec/lib/rex/exploitation/jsobfu_spec.rb
index b788dc3515..e8eba7a7fc 100644
--- a/spec/lib/rex/exploitation/jsobfu_spec.rb
+++ b/spec/lib/rex/exploitation/jsobfu_spec.rb
@@ -1,3 +1,4 @@
+require 'spec_helper'
 require 'rex/exploitation/jsobfu'
 
 describe Rex::Exploitation::JSObfu do
@@ -12,13 +13,21 @@ describe Rex::Exploitation::JSObfu do
     it { should be_a String }
     it { should_not be_empty }
 
+    it 'is alphanumeric' do
+      expect(random_var_name).to match(/\A[a-zA-Z0-9]+\Z/)
+    end
+
+    it 'does not start with a number' do
+      expect(random_var_name).not_to match(/\A[0-9]/)
+    end
+
     context 'when a reserved word is generated' do
       let(:reserved)  { described_class::RESERVED_KEYWORDS.first }
       let(:random)    { 'abcdef' }
       let(:generated) { [reserved, reserved, reserved, random] }
 
       before do
-        Rex::Text.stub(:rand_text_alpha) { generated.shift }
+        jsobfu.stub(:random_string) { generated.shift }
       end
 
       it { should eq random }
@@ -31,7 +40,7 @@ describe Rex::Exploitation::JSObfu do
       let(:generated)   { [preexisting, preexisting, preexisting, random] }
 
       before do
-        Rex::Text.stub(:rand_text_alpha) { generated.shift }
+        jsobfu.stub(:random_string) { generated.shift }
         jsobfu.instance_variable_set("@vars", vars)
       end