It may not have been identified specifically as an Android exploit -- there are people (I used to be one of them, though I wouldn't have used the result to expl

It may not have been identified specifically as an Android exploit -- there are people (I used to be one of them, though I wouldn't have used the result to exploit wallets) who constantly run crypto attacks on transactions in the blockchain to identify weak wallet keys. The person who stole the BTC probably automated the attack, left it running against the blockchain, and never even knew what the real vulnerability was.