diff --git a/lib/msf/core/post/windows/runas.rb b/lib/msf/core/post/windows/runas.rb
index de572ee446..4346e9e65d 100644
--- a/lib/msf/core/post/windows/runas.rb
+++ b/lib/msf/core/post/windows/runas.rb
@@ -42,7 +42,7 @@ module Msf::Post::Windows::Runas
   end
 
   #
-  # Create a STARTUP_INFO struct for use with CreateProcessa
+  # Create a STARTUP_INFO struct for use with CreateProcessA
   #
   # This struct will cause the process to be hidden
   #
@@ -192,6 +192,9 @@ module Msf::Post::Windows::Runas
   # @return [Hash] The values from the process_information struct
   #
   def parse_process_information(process_information)
+    fail ArgumentError, 'process_information is nil' if process_information.nil?
+    fail ArgumentError, 'process_information is empty string' if process_information.empty?
+
     pi = process_information.unpack('LLLL')
     { :process_handle => pi[0], :thread_handle => pi[1], :process_id => pi[2], :thread_id => pi[3] }
   end
@@ -208,6 +211,8 @@ module Msf::Post::Windows::Runas
   # @return [True] True if username is in the correct format
   #
   def check_user_format(username, domain)
+    fail ArgumentError, 'username is nil' if username.nil?
+
     if domain && username.include?('@')
       raise ArgumentError, 'Username is in UPN format (user@domain) so the domain parameter must be nil'
     end
@@ -230,12 +235,17 @@ module Msf::Post::Windows::Runas
   # @return [True] True if the command_line is within the correct bounds
   #
   def check_command_length(application_name, command_line, max_length)
+    fail ArgumentError, 'max_length is nil' if max_length.nil?
+
     if application_name.nil? && command_line.nil?
       raise ArgumentError, 'Both application_name and command_line are nil'
-    elsif application_name.nil? && command_line && command_line.length > MAX_PATH
-      raise ArgumentError, "When application_name is nil the command line must be less than MAX_PATH #{MAX_PATH} characters (Currently #{command_line.length})"
-    elsif application_name && command_line && command_line.length > max_length
-      raise ArgumentError, "When application_name is set, command line must be less than #{max_length} characters (Currently #{command_line.length})"
+    elsif command_line && command_line.length > max_length
+      raise ArgumentError, "Command line must be less than #{max_length} characters (Currently #{command_line.length})"
+    elsif application_name.nil? && command_line
+      cl = command_line.split(' ')
+      if cl[0] && cl[0].length > MAX_PATH
+        raise ArgumentError, "When application_name is nil the command line module must be less than MAX_PATH #{MAX_PATH} characters (Currently #{cl[0].length})"
+      end
     end
 
     true
diff --git a/spec/lib/msf/core/post/windows/runas_spec.rb b/spec/lib/msf/core/post/windows/runas_spec.rb
new file mode 100644
index 0000000000..1106fecade
--- /dev/null
+++ b/spec/lib/msf/core/post/windows/runas_spec.rb
@@ -0,0 +1,207 @@
+# -*- coding: binary -*-
+require 'spec_helper'
+
+require 'msf/core/post/windows/runas'
+
+describe Msf::Post::Windows::Runas do
+  let(:process_info) do
+    "\x01\x00\x00\x00\x02\x00\x00\x00\x03\x00\x00\x00\x04\x00\x00\x00"
+  end
+
+  let(:phToken) do
+    "testPhToken"
+  end
+
+  let(:advapi32) do
+    advapi32 = double('advapi32')
+    advapi32.stub(:CreateProcessWithLogonW).and_return(
+                        'return' => true,
+                        'lpProcessInformation' => process_info
+                     )
+    advapi32.stub(:CreateProcessAsUserA).and_return ({
+      'return' => true,
+      'lpProcessInformation' => process_info
+    })
+    advapi32.stub(:LogonUserA).and_return ({
+      'return' => true,
+      'phToken' => phToken
+    })
+    advapi32
+  end
+
+  let(:kernel32) do
+    double('kernel32', CloseHandle: nil)
+  end
+
+  subject do
+    mod = Module.new
+    mod.extend described_class
+    stubs = [ :vprint_status, :print_status, :vprint_good, :print_good, :print_error ]
+    stubs.each { |meth| mod.stub(meth) }
+    mod.stub_chain("session.railgun.kernel32").and_return(kernel32)
+    mod.stub_chain("session.railgun.advapi32").and_return(advapi32)
+    mod
+  end
+
+  context "#create_process_with_logon" do
+    it "should return a process_info hash" do
+      expect(advapi32).to receive(:CreateProcessWithLogonW)
+      expect(kernel32).not_to receive(:CloseHandle)
+      pi = subject.create_process_with_logon(nil, 'bob', 'pass', nil, 'cmd.exe')
+      pi.should be_kind_of(Hash)
+      pi.should eq(process_handle: 1, thread_handle: 2, process_id: 3, thread_id: 4)
+    end
+
+    it "should return a nil on failure" do
+      expect(advapi32).to receive(:CreateProcessWithLogonW)
+      expect(kernel32).not_to receive(:CloseHandle)
+      advapi32.stub(:CreateProcessWithLogonW).and_return('return' => false, 'GetLastError' => 1783, 'ErrorMessage' => 'parp')
+      subject.create_process_with_logon(nil, 'bob', 'pass', nil, 'cmd.exe').should be nil
+    end
+  end
+
+  context "#create_process_as_user" do
+    it "should return a process_info hash" do
+      expect(advapi32).to receive(:LogonUserA)
+      expect(advapi32).to receive(:CreateProcessAsUserA)
+      expect(kernel32).to receive(:CloseHandle).with(phToken)
+      expect(kernel32).to receive(:CloseHandle).with(1)
+      expect(kernel32).to receive(:CloseHandle).with(2)
+      pi = subject.create_process_as_user(nil, 'bob', 'pass', nil, 'cmd.exe')
+      pi.should be_kind_of(Hash)
+      pi.should eq(process_handle: 1, thread_handle: 2, process_id: 3, thread_id: 4)
+    end
+
+    it "should return a nil on failure of create process" do
+      expect(advapi32).to receive(:LogonUserA)
+      expect(advapi32).to receive(:CreateProcessAsUserA)
+      expect(kernel32).to receive(:CloseHandle).with(phToken)
+      expect(kernel32).not_to receive(:CloseHandle).with(1)
+      expect(kernel32).not_to receive(:CloseHandle).with(2)
+      advapi32.stub(:CreateProcessAsUserA).and_return('return' => false, 'GetLastError' => 1783, 'ErrorMessage' => 'parp')
+      subject.create_process_as_user(nil, 'bob', 'pass', nil, 'cmd.exe').should be nil
+    end
+
+    it "should return a nil on failure of logon user" do
+      expect(advapi32).to receive(:LogonUserA)
+      expect(advapi32).not_to receive(:CreateProcessAsUserA)
+      expect(kernel32).not_to receive(:CloseHandle).with(phToken)
+      expect(kernel32).not_to receive(:CloseHandle).with(1)
+      expect(kernel32).not_to receive(:CloseHandle).with(2)
+      advapi32.stub(:LogonUserA).and_return('return' => false, 'GetLastError' => 1783, 'ErrorMessage' => 'parp')
+      subject.create_process_as_user(nil, 'bob', 'pass', nil, 'cmd.exe').should be nil
+    end
+  end
+
+  context "#startup_info" do
+    it "should be 68 bytes" do
+      subject.startup_info.size.should eq(68)
+    end
+
+    it "should return SW_HIDE=0 and STARTF_USESHOWWINDOW=1" do
+      si = subject.startup_info.unpack('VVVVVVVVVVVVvvVVVV')
+      si[11].should eq(1)
+      si[12].should eq(0)
+    end
+  end
+
+  context "#parse_process_information" do
+    it "should return a hash when given valid data" do
+      pi = subject.parse_process_information(process_info)
+      pi.should be_kind_of(Hash)
+      pi.should eq(process_handle: 1, thread_handle: 2, process_id: 3, thread_id: 4)
+    end
+
+    it "should return an exception when given an empty string" do
+      expect { subject.parse_process_information("") }.to raise_error
+    end
+
+    it "should return an exception when given an nil value" do
+      expect { subject.parse_process_information(nil) }.to raise_error
+    end
+  end
+
+  context "#check_user_format" do
+    let(:upn_username) do
+      "bob@flob.com"
+    end
+    let(:domain_username) do
+      "flob\\bob"
+    end
+    let(:domain) do
+      "flob"
+    end
+
+    it "should return an exception when username is nil" do
+      expect { subject.check_user_format(nil, domain) }.to raise_error
+    end
+
+    it "should return an exception when UPN format and domain supplied" do
+      expect { subject.check_user_format(upn_username, domain) }.to raise_error
+    end
+
+    it "should return true when UPN format and domain is nil" do
+      subject.check_user_format(upn_username, nil).should be true
+    end
+
+    it "should return true when domain format and domain is nil" do
+      subject.check_user_format(domain_username, nil).should be true
+    end
+
+    it "should return true when domain format and domain supplied" do
+      subject.check_user_format(domain_username, domain).should be true
+    end
+  end
+
+  context "#check_command_length" do
+    let(:max_length) do
+      1024
+    end
+    let(:max_path) do
+      256
+    end
+    let(:large_command_module) do
+      ("A" * max_path + 1) + " arg1 arg2"
+    end
+    let(:normal_command_module) do
+      ("A" * max_path) + " arg1 arg2"
+    end
+    let(:large_command_line) do
+      "A" * max_length + 1
+    end
+    let(:normal_command_line) do
+      "A" * max_length
+    end
+    let(:application_name) do
+      "c:\\windows\\system32\\calc.exe"
+    end
+
+    it "should raise an exception when max_length is nil" do
+      expect { subject.check_command_length(nil, nil, nil) }.to raise_error
+    end
+
+    it "should raise an exception when application_name and command_line are nil" do
+      expect { subject.check_command_length(nil, nil, max_length) }.to raise_error
+    end
+
+    it "should return true when application_name is set and command_line is nil" do
+      subject.check_command_length(application_name, nil, max_length).should be true
+    end
+
+    it "should return true when application_name is set and command_line is max_length" do
+      subject.check_command_length(application_name, normal_command_line, max_length).should be true
+    end
+
+    it "should raise an exception when command_line is larger than max_length" do
+      expect { subject.check_command_length(nil, large_command_line, max_length) }.to raise_error
+    end
+
+    it "should raise an exception when application_name is nil command_line module is larger than MAX_PATH" do
+      expect { subject.check_command_length(nil, large_command_module, max_length) }.to raise_error
+    end
+
+    it "should return true when application_name is nil and command_module is less than MAX_PATH" do
+      subject.check_command_length(nil, normal_command_module, max_length).should be true
+    end
+  end
+end