"There are journalism ethics to mining emails hacked by someone else," writes Kelly McBride at poynter.org. "But the question is not whether or not to mine them, but rather how."
When faced with information gained by nefarious means, a journalist should:
• Do additional reporting to verify the details. You must be sure it is accurate before you pass it along
• Avoid distortion and instead ensure appropriate tone. This means watching your headlines, adjectives and all the other details that give a particular piece of information a certain tone. When you add flavor to information, it needs to be appropriate.
• Add context, by seeking additional input or rebuttal from the relevant stakeholders. Context makes information more accurate.
"The ethics of hacked email and otherwise ill-gotten information" [poynter.org]