FatMan

The problem with having no duplicate check is an attacker can create a short position, and after 14 days, they could call their position ID multiple times in a list. This would let them steal funds from the lock contract over and over at little cost and zero risk. (4/12)

So - this bug exists and was quietly patched up - but we don't know if anyone ever noticed it or exploited it before. It would be hard to check since you would need to sift through months of chain data and millions of transactions - the Mirror forum didn't bother. (5/12)

Call it luck, magic, or God's will - whatever you believe in - a source fell into my lap inadvertently revealing that this attack had indeed been executed hundreds of times since 2021. Before today, this was not known by anyone at all. Let's go meet the attacker, shall we? (6/12)

The lock contract didn't check that the funds were sent from the mint contract, so the attacker opened a position with $10 in collateral (!) and send $10k directly to the lock contract. They could then loop-unlock others' collateral over and over again from the contract. (10/12)

In one transaction, the attacker turned $10,000 into $4,300,000. This was actually done several times, generating a total of well over $30m. All of this went completely unnoticed by TFL and the Mirror team & community. This is the first time this attack has been revealed. (11/12)