Somewhere, a group is preparing an attack on Bitcoin. It will come around the next big pump. The attackers will have an exponentially large advantage of computing power. If the network isn't compromised, it will be severely damaged.
Are you talking about a 51% attack? That may be possible with some of the little known cryptocurrencies, but not with Bitcoin. For launching a 51% attack on BTC, you need millions of mining rigs and many Gigawatts of electricity. I don't think that all these can be procured on short notice. Is there any evidence of an impending attack? Else, please refrain from spreading FUD here.