Impersonating online aliases of real people is considered a form of Impersonating people with the intention of identity theft or to make them look mentally ill or like a criminal, or otherwise pervert their appearance or presence/intent is a violation of title 18.
So is impersonating a web interface to harvest peoples private information and steal their identities.
We don't need more laws around cyber security, it's already a felony with intent for most internet crimes.