I'll explain in point form as it will be easy for readers to understand and test the scenario. (I have tested this in DSS 3.2.2 version)
1) downloaded "cors-filter-2.4.jar" and "java-property-utils-1.9.1.jar" from the site [1] and added those jars to DSS/repository/components/lib folder
2) added below config elements to DSS/repository/conf/tomcat/web.xml file
3) restarted the DSS and then CORS will work fine nowCORS com.thetransactioncompany.cors.CORSFilter CORS /*
PS - you can fine tune url pattern to allow this to limited url patterns. for example you can use pattern as below
using this you can fine tune it to allow CORS for only some of the services hosted in DSS/services/*
[1] - http://software.dzhuvinov.com/cors-filter-installation.html
Hope this helps :-)