Fix guessing the arch with modules specifying an array

Author: zeroSteiner

lib/msf/core/exploit/local/windows_kernel.rb

@@ -115,7 +115,10 @@ def open_device(file_name, desired_access, share_mode, creation_disposition, fla
   #
   def token_stealing_shellcode(target, arch = nil)
     arch = target.opts['Arch'] if arch.nil? && target && target.opts['Arch']
-    arch = module_info['Arch'] if arch.nil? && module_info['Arch']
+    if arch.nil? && module_info['Arch']
+      arch = module_info['Arch']
+      arch = arch[0] if arch.class.to_s == 'Array' and arch.length == 1
+    end
     if arch.nil?
       print_error('Can not determine the target architecture')
       fail ArgumentError, 'Invalid arch'