The western intelligence community should respond with their own wikileaks style dump of data they have on the matter.
One of the great appeals of the Russian propaganda outlet Wikileaks, is the open data nature of the documents.
For example, in regards to the DNC hack, the data surrounding how it was ascertained that Russian hackers were responsible, should be released.
Donald Trump’s entire tax history should be released.
The CIA etc wouldn’t necessarily have to publish the data themselves. Who knows what the level of direct collusion between Putin and Assange is, but the CIA could similarly leak data to a friendly hactivist type organisation. Or directly to the Washington Post I suppose.
It’s apparent that you can use data leaking and data manipulation (eg. Twitter bots, paid trolls) to quite an effect. The Western intelligence community should perhaps consider responding in kind. After all, intelligence warfare is quite a peaceful kind of warfare. If all conflicts were just releasing embarrassing data about each other, that could be awful in its own right, but apparently better than dying a bloody death.