I think the whole world has a terrorism problem. Even countries that have traditionally been very neutral and peaceful are having problems with young men committing acts of terrorist aggression. It's everywhere now.
I don't think it is a problem of fixing security, as most terrorists are "home grown," they don't come in from outside countries. The home grown terrorists very likely are influenced by things going on in other countries, but usually they are natives to the country they terrorize.
It's a problem of raising better kids. Of doing the hard thing to keep your child off the streets and away from drugs and guns. Of making people understand why hurting others is more than just unethical or immoral, it's a path toward self-destruction and misery for everyone. And, we ought to be assigning more officers to ensure people go make their mental health appointments, as everyone should be doing.
The world of human beings is as sick place. Men value the wrong things and the wrong ideas. And especially young, gullible, highly impressionable men. We need to make sure resources are available and utlilized to keep young men in school and out of trouble and to get counseling. Most of them need it very badly. And we need to pass strict gun control measures - not a popular sentiment, but an accurate one. It has to happen or we'll never be able to overcome this dilemma at all.