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I was offered $500k as a thank-you bounty for pilfering $600m from Poly Network, says crypto-thief

The mysterious miscreant who exploited a software vulnerability in Poly Network to drain $600m in crypto-assets, claims the Chinese blockchain company offered them $500,000 as a reward for discovering the weakness.

Most of the digital funds have been returned over several transactions. “We appreciate you sharing your experience and believe your action constitutes white hat behaviour … Since, we believe your action is white hat behaviour, we plan to offer you a $500,000 bug bounty after you complete the refund fully,” the thief wrote in their transaction metadata, seemingly quoting or paraphrasing a message received from Poly Network.

The miscreant claims Poly Networks offered the money as part of a “completely legal bounty reward,” and the biz told him it believed the massive heist “is white hat behavior.” However, it appears the thief won’t accept the bounty, and may instead send back the rest of the digital dosh.

In a statement, Poly Network referred to the miscreant as “Mr White Hat,” and said it hasn’t recovered all the stolen tokens yet. “To achieve the goal of full recovery of both assets and cross-chain services, the team will continue to communicate with Mr White Hat actively to retrieve the final key,” it added.

Poly Network said the crypto-pickpocket had returned about $260m out of the $600m digital assets on Wednesday, and is in the process of transferring another $238m back.

The so-called “Mr White Hat” exploited a vulnerability in Poly Network’s execution of smart contracts – programs that run when a specific set of conditions agreed between participants are met – that were used in exchanging tokens and crypto-currencies. Hundreds of millions of dollars in various assets held in multiple blockchain platforms were drained.

In a series of FAQ posts shared by Tom Robinson, chief scientist at crypto-coin analysis house Elliptic, the thief said they were not interested in keeping the money and had instead broken into Poly Network for fun and to raise awareness of the hole in Poly’s security. They also gave away a few clues on their identity, and claimed they were “a high-profile hacker in the real world” working in the security industry and a non-native English speaker. ®