A Man in the Middle (MITM) attack is where the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating with each other.
Hardware wallets such as the Ledger Nano are viewed as one of the safest ways to store large amounts of coins and keep them out of the hands of hackers. Hardware wallets such as the Ledger offer an isolation layer between the computer and the seed (the wallets private keys). Even so, users should always make sure that they are sending coins to the correct address when transacting.
A Man in the Middle attack could replace the receiving address on a computer with another one, tricking the user into sending funds to an unintended third-party (possibly the attacker).
How To Avoid A Man in the Middle Attack?
It is impossible to 100% trust what you see displayed on your computer screen – remember that. The one thing users can trust is what you see displayed on the Ledger hardware wallet screen, so make sure you always verify the address on the Ledger screen before sending funds.
You can also make use of the Ledger Wallet Bitcoin Chrome application which also has a dedicated icon (see image below) allowing the user to display the receiving address on their Ledger device. When the user clicks on this icon, the correct address is generated by the wallet and displayed on the Ledger hardware wallet’s screen. What you see on your device is the only information you can trust!