We had heard rumors yesterday that Asiana was considering legal action because of the incident, but today they confirmed that is what they will do. The airline says that the report did "major damage to their reputation."
Looking at it another way, it also damaged the reputation of KTVU, since they reported the series of obviously fake names, and the NTSB, since their random summer intern confirmed it.
Asiana decided to only sue KTVU because their report is what damaged them. The suits will be filed in US courts.