That possible to happen that smart hackers or us if we have skills on how to hack gambling site. Most hackers will attack if they know that the site has a system bug problem and it is easy for them to enter the wallet of the gambling site. That recently happen on Windice gambling site, the mod announced that our wallet was temporarily freezing to verify the hacker's account.
Dear bitcointalk users!
We encountered a problem: a critical bug was discovered that allowed some of the players to get access to the server seed.
Unfortunately , the users didn't report the bug , but attempted to abuse it instead. Due to the fact that windice.io has instant withdrawals, our hot wallets were drained for over 3 bitcoins in total.
Information is given here.