diff --git a/lib/brakeman/checks/base_check.rb b/lib/brakeman/checks/base_check.rb
index 11c5cd3f6253d5f75bc57c7924432616754dd1dc..6b0120b3ad7e669f5b285a979b59f68e1e791f21 100644
--- a/lib/brakeman/checks/base_check.rb
+++ b/lib/brakeman/checks/base_check.rb
@@ -1,11 +1,10 @@
-require 'sexp_processor'
 require 'brakeman/processors/output_processor'
 require 'brakeman/processors/lib/processor_helper'
 require 'brakeman/warning'
 require 'brakeman/util'
 
 #Basis of vulnerability checks.
-class Brakeman::BaseCheck < SexpProcessor
+class Brakeman::BaseCheck < Brakeman::SexpProcessor
   include Brakeman::ProcessorHelper
   include Brakeman::Util
   attr_reader :tracker, :warnings
@@ -24,11 +23,6 @@ class Brakeman::BaseCheck < SexpProcessor
     @current_set = nil
     @current_template = @current_module = @current_class = @current_method = nil
     @mass_assign_disabled = nil
-    self.strict = false
-    self.auto_shift_type = false
-    self.require_empty = false
-    self.default_method = :process_default
-    self.warn_on_default = false
   end
 
   #Add result to result list, which is used to check for duplicates
diff --git a/lib/brakeman/processors/alias_processor.rb b/lib/brakeman/processors/alias_processor.rb
index e1fdef05cca66e318281c3dac89c464bb5bc040d..c9b4291dd9bf085001f8191c30ff4d281766dc98 100644
--- a/lib/brakeman/processors/alias_processor.rb
+++ b/lib/brakeman/processors/alias_processor.rb
@@ -1,12 +1,11 @@
-require 'rubygems'
-require 'sexp_processor'
 require 'brakeman/util'
+require 'ruby_parser/bm_sexp_processor'
 require 'brakeman/processors/lib/processor_helper'
 
 #Returns an s-expression with aliases replaced with their value.
 #This does not preserve semantics (due to side effects, etc.), but it makes
 #processing easier when searching for various things.
-class Brakeman::AliasProcessor < SexpProcessor
+class Brakeman::AliasProcessor < Brakeman::SexpProcessor
   include Brakeman::ProcessorHelper
   include Brakeman::Util
 
@@ -19,11 +18,6 @@ class Brakeman::AliasProcessor < SexpProcessor
   # AliasProcessor.new.process_safely src
   def initialize tracker = nil
     super()
-    self.strict = false
-    self.auto_shift_type = false
-    self.require_empty = false
-    self.default_method = :process_default
-    self.warn_on_default = false
     @env = SexpProcessor::Environment.new
     @inside_if = false
     @ignore_ifs = false
diff --git a/lib/brakeman/processors/base_processor.rb b/lib/brakeman/processors/base_processor.rb
index c67c0b43768cc3ba01db29c18302ca90a108288c..53fc26533b03a8ac4577539c7882390fbe332e5d 100644
--- a/lib/brakeman/processors/base_processor.rb
+++ b/lib/brakeman/processors/base_processor.rb
@@ -1,10 +1,8 @@
-require 'rubygems'
-require 'sexp_processor'
 require 'brakeman/processors/lib/processor_helper'
 require 'brakeman/util'
 
 #Base processor for most processors.
-class Brakeman::BaseProcessor < SexpProcessor
+class Brakeman::BaseProcessor < Brakeman::SexpProcessor
   include Brakeman::ProcessorHelper
   include Brakeman::Util
 
@@ -13,11 +11,6 @@ class Brakeman::BaseProcessor < SexpProcessor
   #Return a new Processor.
   def initialize tracker
     super()
-    self.strict = false
-    self.auto_shift_type = false
-    self.require_empty = false
-    self.default_method = :process_default
-    self.warn_on_default = false
     @last = nil
     @tracker = tracker
     @ignore = Sexp.new :ignore
@@ -50,7 +43,7 @@ class Brakeman::BaseProcessor < SexpProcessor
   #Default processing.
   def process_default exp
     exp = exp.dup
-    type = exp.shift
+
     exp.each_with_index do |e, i|
       if sexp? e and not e.empty?
         exp[i] = process e
@@ -58,8 +51,8 @@ class Brakeman::BaseProcessor < SexpProcessor
         e
       end
     end
-  ensure
-    exp.unshift type
+
+    exp
   end
 
   #Process an if statement.
diff --git a/lib/brakeman/processors/template_processor.rb b/lib/brakeman/processors/template_processor.rb
index bda89ed794294135f63649b6d0b4729f9181b70b..0e95fb7a3c1a34df6eaad51a07e601cea4078702 100644
--- a/lib/brakeman/processors/template_processor.rb
+++ b/lib/brakeman/processors/template_processor.rb
@@ -20,7 +20,6 @@ class Brakeman::TemplateProcessor < Brakeman::BaseProcessor
     tracker.templates[template_name] = @current_template
 
     @inside_concat = false
-    self.warn_on_default = false
   end
 
   #Process the template Sexp.
diff --git a/lib/brakeman/scanner.rb b/lib/brakeman/scanner.rb
index b62d3b0e26234728ef4bf6845e2f53ffa18fbae6..b3910eb1ba055674103cd344e8866ddb03b8fc14 100644
--- a/lib/brakeman/scanner.rb
+++ b/lib/brakeman/scanner.rb
@@ -8,6 +8,8 @@ begin
     require 'ruby_parser/bm_sexp.rb'
   end
 
+  require 'ruby_parser/bm_sexp_processor.rb'
+
   require 'haml'
   require 'sass'
   require 'erb'
diff --git a/lib/brakeman/util.rb b/lib/brakeman/util.rb
index 63e96b6b04e45a41cd3b7f2bbd428c9734b84022..ddc93a2b2610be5005a80999c4f25eeb5bf140a3 100644
--- a/lib/brakeman/util.rb
+++ b/lib/brakeman/util.rb
@@ -1,4 +1,3 @@
-require 'sexp_processor'
 require 'set'
 require 'active_support/inflector'
 
diff --git a/lib/ruby_parser/bm_sexp_processor.rb b/lib/ruby_parser/bm_sexp_processor.rb
new file mode 100644
index 0000000000000000000000000000000000000000..db1588d2cfadb873c88540415619d9a720e468aa
--- /dev/null
+++ b/lib/ruby_parser/bm_sexp_processor.rb
@@ -0,0 +1,231 @@
+##
+# SexpProcessor provides a uniform interface to process Sexps.
+#
+# In order to create your own SexpProcessor subclass you'll need
+# to call super in the initialize method, then set any of the
+# Sexp flags you want to be different from the defaults.
+#
+# SexpProcessor uses a Sexp's type to determine which process method
+# to call in the subclass.  For Sexp <code>s(:lit, 1)</code>
+# SexpProcessor will call #process_lit, if it is defined.
+#
+
+class Brakeman::SexpProcessor
+
+  VERSION = 'CUSTOM'
+
+  ##
+  # Return a stack of contexts. Most recent node is first.
+
+  attr_reader :context
+
+  ##
+  # Expected result class
+
+  attr_accessor :expected
+
+  ##
+  # A scoped environment to make you happy.
+
+  attr_reader :env
+
+  ##
+  # Creates a new SexpProcessor.  Use super to invoke this
+  # initializer from SexpProcessor subclasses, then use the
+  # attributes above to customize the functionality of the
+  # SexpProcessor
+
+  def initialize
+    @expected            = Sexp
+
+    # we do this on an instance basis so we can subclass it for
+    # different processors.
+    @processors = {}
+    @context    = []
+
+    public_methods.each do |name|
+      if name.to_s.start_with? "process_" then
+        @processors[name[8..-1].to_sym] = name.to_sym
+      end
+    end
+  end
+
+  ##
+  # Default Sexp processor.  Invokes process_<type> methods matching
+  # the Sexp type given.  Performs additional checks as specified by
+  # the initializer.
+
+  def process(exp)
+    return nil if exp.nil?
+
+    result = nil
+
+    type = exp.first
+    raise "type should be a Symbol, not: #{exp.first.inspect}" unless
+      Symbol === type
+
+    in_context type do
+      # now do a pass with the real processor (or generic)
+      meth = @processors[type]
+      if meth then
+        if $DEBUG
+          result = error_handler(type) do
+            self.send(meth, exp)
+          end
+        else
+          result = self.send(meth, exp)
+        end
+
+      else
+        result = self.process_default(exp)
+      end
+    end
+    
+    raise SexpTypeError, "Result must be a #{@expected}, was #{result.class}:#{result.inspect}" unless @expected === result
+    
+    result
+  end
+
+  def error_handler(type, exp=nil) # :nodoc:
+    begin
+      return yield
+    rescue StandardError => err
+      warn "#{err.class} Exception thrown while processing #{type} for sexp #{exp.inspect} #{caller.inspect}" if $DEBUG
+      raise
+    end
+  end
+
+  ##
+  # A fairly generic processor for a dummy node. Dummy nodes are used
+  # when your processor is doing a complicated rewrite that replaces
+  # the current sexp with multiple sexps.
+  #
+  # Bogus Example:
+  #
+  #   def process_something(exp)
+  #     return s(:dummy, process(exp), s(:extra, 42))
+  #   end
+
+  def process_dummy(exp)
+    result = @expected.new(:dummy) rescue @expected.new
+
+    until exp.empty? do
+      result << self.process(exp.shift)
+    end
+
+    result
+  end
+
+  ##
+  # Add a scope level to the current env. Eg:
+  #
+  #   def process_defn exp
+  #     name = exp.shift
+  #     args = process(exp.shift)
+  #     scope do
+  #       body = process(exp.shift)
+  #       # ...
+  #     end
+  #   end
+  #
+  #   env[:x] = 42
+  #   scope do
+  #     env[:x]       # => 42
+  #     env[:y] = 24
+  #   end
+  #   env[:y]         # => nil
+
+  def scope &block
+    env.scope(&block)
+  end
+
+  def in_context type
+    self.context.unshift type
+
+    yield
+
+    self.context.shift
+  end
+
+  ##
+  # I really hate this here, but I hate subdirs in my lib dir more...
+  # I guess it is kinda like shaving... I'll split this out when it
+  # itches too much...
+
+  class Environment
+    def initialize
+      @env = []
+      @env.unshift({})
+    end
+
+    def all
+      @env.reverse.inject { |env, scope| env.merge scope }
+    end
+
+    def depth
+      @env.length
+    end
+
+    # TODO: depth_of
+
+    def [] name
+      hash = @env.find { |closure| closure.has_key? name }
+      hash[name] if hash
+    end
+
+    def []= name, val
+      hash = @env.find { |closure| closure.has_key? name } || @env.first
+      hash[name] = val
+    end
+
+    def scope
+      @env.unshift({})
+      begin
+        yield
+      ensure
+        @env.shift
+        raise "You went too far unextending env" if @env.empty?
+      end
+    end
+  end
+end
+
+class Object
+
+  ##
+  # deep_clone is the usual Marshalling hack to make a deep copy.
+  # It is rather slow, so use it sparingly. Helps with debugging
+  # SexpProcessors since you usually shift off sexps.
+
+  def deep_clone
+    Marshal.load(Marshal.dump(self))
+  end
+end
+
+##
+# SexpProcessor base exception class.
+
+class SexpProcessorError < StandardError; end
+
+##
+# Raised by SexpProcessor if it sees a node type listed in its
+# unsupported list.
+
+class UnsupportedNodeError < SexpProcessorError; end
+
+##
+# Raised by SexpProcessor if it is in strict mode and sees a node for
+# which there is no processor available.
+
+class UnknownNodeError < SexpProcessorError; end
+
+##
+# Raised by SexpProcessor if a processor did not process every node in
+# a sexp and @require_empty is true.
+
+class NotEmptyError < SexpProcessorError; end
+
+##
+# Raised if assert_type encounters an unexpected sexp type.
+
+class SexpTypeError < SexpProcessorError; end