This wasn't a third party wallet actually. It is the local Parity wallet and node. What this was, was a bug in the multisig contract that Parity would give you to deploy. So it is a contract you personally deploy onto the ethereum network and then interact with. You do own it, you own the private keys for the address, etc.
But the bug allowed any other address to add themselves as owners and withdraw from it.
Luckily not many people used it and the white hat was able to claim all the rest before anyone else.
But the bug allowed any other address to add themselves as owners and withdraw from it.
Luckily not many people used it and the white hat was able to claim all the rest before anyone else.