Not sure exactly what type attacks they will try. The reality is that more people are watching Fox News because the liberal progressive left media has demonstrated a disregard for the truth, in favor of petty partisan bickering and misleading news coverage. They're trying to score liberal points against Fox News. Fox News viewers has been growing tremendously because of the MSM's deceptive skewing of the truth for it's partisan political agenda. They can attack all the conservative media outlets they want. Every time they do the voters see that Fox News is telling the truth, and George Soros, Media Matters, and the MSM are trying to manufacture bogus attacks on Fox News to deceive the American voter. Every time they attack they lose a few more Americans to Fox News and to Tea Party / GOP / Conservative groups. Go for it George. Knock yourself out.
Note: Media Matters is classified as a tax deductible charity 501(c). Charities are not allowed to play partisan politics. Attacking Fox is illegal because it is participating in partisan politics. Media Matters is breaking the law and I'll bet that AG Eric Holder does nothing.
source: http://www.politico.com/news/stories/0311/51949.html