Wallet generator is the most popular website for creating most secure cold storage wallets called - paper wallets for loads of coins.
Currently when this issue of 1:1 copy of website was found the site itself is turned off https://walletgenerator.org/ (some people speak about ddos going on it)
So the developer verified that only secure website is https://walletgenerator.net/
Most secure way
The best way is to actually download the script, put it on computer than never been on internet or at least took off internet connection and then generate https://github.com/MichaelMure/WalletGenerator.net/archive/master.zip from here.
The fake copy of website was found just 8 hours ago, its possible it was running for over a month.
If you have generated paper wallets lately make sure you have used proper source or move coins ASAP.