Good to Know
You need ETH on Ethereum Mainnet for both the registration fee and gas.
Registration involves two transactions and takes about 3 minutes.
This article explains the process — for step-by-step instructions, see How to Register a .eth Name.
There are three steps involved in registering an ENS name that is intended to mitigate the problem of front-running. Front-running an ENS name would be possible if registration happened in one transaction. Someone could “see” the single registration transaction in the mempool, and send the same transaction but with higher gas so the transaction they sent settles first. In essence, “sniping” the name before registration completes. For this reason, ENS name registrations rely on a Reveal-Commitment Scheme.
For a step on step guide see How to Register a .eth Name
Three Step Process
Step 1: Request to register
The commit in Step 1 hashes a secret key generated and stored in your browser's local storage and hashes it with your wallet address and ENS name so that you can later register it without revealing it publicly.
Only the user knows the values of the cryptographic hash.
Once you've performed the Request to Register you have 24 hours to complete Step 3 until the Request to Register becomes invalid.
No registration fees are collected in this step. The fees are only for gas to save the commit transaction onchain.
Keep in mind that while you have 24 hours to complete the name registration, the name is not reserved for you during this time.
Clearing your browser cache will lose the saved commit, and start the registration process over again.
Step 2: Wait for 1 minute
A 1 minute waiting period begins to prevent the front-running of the ENS name registration. This wait period acts as a “buffer” so that in the final step, the revealed ENS name’s registration cannot be front-run with a higher gas transaction.
Step 3: Register
The ENS name registration is revealed onchain. Once the registration transaction is performed and the ENS name is registered; the ERC-721 NFT or (wrapped) ERC-1155 NFT for the ENS name is minted and transferred into the owner's wallet.
In conclusion
If a miner wanted to try and front-run this process, they would have to send their own hashed secret, wait 1 minute and then register the name. Since The 3 step registration process works because they can't hold back your transaction for one minute, they will fail to do so, and the miner can't use the secret compared to the earlier hash.