No it wouldn't though. If it was a country, it would be easy for both Russia and America, yes. But because ISIS is an ideology, you can't take it down with immediate force. An attack of that magnitude will only draw sympathy and more support for ISIS, even if it is entirely unjustified.
ISIS are more barbaric than any other Islamic terrorist cells are, but I don't know whether that's a blessing or a curse for them. They are far more bold and have made significant land gains, but the question is whether they can hold onto them or not without the risk of intervention from the rest of the Arabian world, or even rebellions within their controlled territories. Add to that the multitude of ways their ideology can be interpreted (they decapitated one of their head executioners for smoking), and you have a force that will self destruct on itself.