The typical way to do this is to capture this data with hidden fields in the Marketo forms, using the "cookie value" feature for hidden fields.
so create the UTM's fields in Marketo, add them to your forms, then in the field properties in the form, change the type to hidden. The hit the "Autofill" edit link:
Finally, in the autofill, choose cookie value, and add the cookie name in the parameter name:
YOu can also do this through JS code if you have a developer who knows how to use the forms 2.0 API.