fake RAIL was a backdoored token contract. this section lets the attacker forge permit signatures and transfer any user's balance in the contract. 

this scam is common enough that you can often recognize it from this snippet: if there's weird assembly in here and you don't see "ecrecover" anywhere, it's a backdoor.

To make it simpler :
A malicious actor creates a fake token contract like fake RAIL with a backdoored permit function that allows them to forge signatures and steal tokens from users.

How It Works:
1. permit is supposed to use ecrecover to verify user signatures before allowing token approvals.
2. The scam contract removes ecrecover and uses custom assembly code to bypass signature checks.
3. This lets the attacker generate fake approvals and drain tokens from any user who interacted with the contract.

Red Flags:
I. permit function with weird inline assembly
II. No ecrecover in signature logic
III. Recently deployed or unverified token contracts
IV. Token name copies a real project

If a token has a permit function with custom assembly and no ecrecover, it’s likely malicious. Don’t interact with it , you could lose your tokens.

Soc analyst :-

Un linguiste incroyable qui peut communiquer dans 7 langues différentes, Me encantaría conocerte