How Did the Ethereum Hard Fork Specifically Address the Funds Stolen from the DAO?
The hard fork was implemented by deploying a special smart contract to the new chain. This contract had one purpose: to move all the Ether from The DAO's contract address to a new withdrawal contract, which allowed the original token holders to reclaim their funds.
This was a non-consensus-breaking change for future blocks, but it explicitly modified the state of the blockchain to nullify the effects of the attack.