More than $300m of cryptocurrency has been lost after a series of bugs in a popular digital wallet service led one curious developer to accidentally take control of and then lock up the funds, according to reports.Unlike most cryptocurrency hacks, however, the money wasn’t deliberately taken: it was effectively destroyed by accident.
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On Tuesday Parity revealed that, while fixing a bug that let hackers steal $32m out of few multi-signature wallets, it had inadvertently left a second flaw in its systems that allowed one user to become the sole owner of every single multi-signature wallet.

The user, “devops199”, triggered the flaw apparently by accident. When they realised what they had done, they attempted to undo the damage by deleting the code which had transferred ownership of the funds. Rather than returning the money, however, that simply locked all the funds in those multisignature wallets permanently, with no way to access them.

“This means that currently no funds can be moved out of the multi-sig wallets,” Parity says in a security advisory.

Effectively, a user accidentally stole hundreds of wallets simultaneously, and then set them on fire in a panic while trying to give them back.

Source: ‘$300m in cryptocurrency’ accidentally lost forever due to bug | Technology | The Guardian