all nuclear weapons were removed from Kazakhstan by May 1995.

As to terrorists breaking into a launch control room, it might be possible but it seems unlikely. Those launch centers were designed to withstand a serious attack. Even if someone got inside, the launch codes aren't on site. Those codes have to come from Russia's command authority (Putin). Furthermore, it takes a lot of training to target and launch the missiles. The Russians were, I believe, just as thorough with their training for launch control officers as we were. There's an elaborate procedure that has to be followed to the letter. If their centers are anything like ours, the launch keys are kept in safes. Without the combinations and the launch codes, there won't be any launch.

Personally, I'm more concerned with a civil war breaking out in Pakistan than terrorists taking over control of a Russian missile center. Pakistan has both nuclear devices and missiles, some with a range of over 1000 miles. Those missiles, if launched from a ship, could hit the US. The nuclear devices themselves could be used in any number of unpleasant ways without the missiles.