How can developed states fight off cyber warfare attacks when the party responsible may not be evident?

: How can developed states fight off cyber warfare attacks when the party responsible may not be evident?Research question, hypothesis and findings are expected, as well as opinions on how to answer the research question. At least one source should be a report or data from the website of an intergovernmental organization. The other sources should be a mixture of monographs or academic journals on the subject.In writing this paper consider the essence of cyber warfare and the practicality behind it, as well as its use as a form of irregular warfare.