Miners don't send hashes, they send blocks. Blocks are public information to be broadcast to the entire network. When a miner completes a block, he sends it to nodes that he is connected to. Those nodes verify the block, and if they find it to be valid, they will send the block to the nodes that they are connected to. This peer to peer gossip is how blocks and transactions reach every node in the Bitcoin network.
An attacker an intercept a block, but that won't do anything for him. He would just become another thing relaying the block to nodes on the network.
Miners aren't paid by submitting aa block to something specific. They are paid by including a special transaction in the block which pays them Bitcoin by essentially creating them from nothing. There are rules about what amount this can be, so if it doesn't fit those rules, the block is invalid. The miner essentially pays himself and the rest of the network agrees on whether he is entitled to that payment. An attacker intercepting this cannot change the miner's payment without having to completely redo the proof of work, i.e. mining the block themselves.