If i was a hacker and had access (to my system for example), i could simply hit send and boom - coins sent, at least from the NRS wallet. It's basically wide open, unless i'm totally missing something.
You can encrypt your wallet, then you need to enter a password whenever you try to send coins. If thats not safe enough, you can use multisig addresses. Using those it basically becomes impossible for the attacker to steal your coins unless he has compromised all of your computers. The downside is that it becomes very time consuming to send coins.