Clean environment variables

Author: jvazquez-r7

modules/exploits/windows/local/ms13_097_ie_registry_symlink.rb

@@ -73,6 +73,9 @@ def exploit
       Timeout.timeout(datastore['DELAY']) { super }
     rescue Timeout::Error
     end
+
+    session.railgun.kernel32.SetEnvironmentVariableA("HTA_URL", nil)
+    session.railgun.kernel32.SetEnvironmentVariableA("HTML_URL", nil)
   end
 
   def primer