Crypto exchange Coinsbuy loses $8 million in coordinated two-blockchain attack

Updated 22 hrs agoPublished 23 hrs ago

2 min read

Summary

• An attacker drained $8.07 million from Coinsbuy across TRON and Ethereum in under an hour on Aug. 9, with blockchain researchers linking both chains into a single operation via cross-chain swapper Bridgers.
• Roughly 79% of stolen funds moved through instant exchange FixedFloat across 50 single-use addresses. ChangeNOW froze a six-figure sum, and approximately $542,000 in ETH has not moved.
• Coinsbuy refilled the drained wallets within 24 hours, suggesting private keys were not compromised, but the exchange has not explained how the withdrawal path was accessed.

Crypto exchange Coinsbuy lost more than $8 million in a coordinated attack across TRON and Ethereum on Aug. 9, according to onchain data reviewed by blockchain security researchers.

The attacker began with a 5 USDT transaction before draining eight TRON wallets of 6.04 million of the dollar-pegged stablecoin in about an hour. On Ethereum, three wallets were simultaneously emptied of 1.89 million USDT and 77 ETH, which was swapped to ETH via 1inch through a wallet created the same day.

Onchain records show the two chains were linked through cross-chain swapper Bridgers, whose Ethereum payout contract sent funds directly into the Ethereum swap wallet, connecting what appeared to be separate operations into a single incident.

The attacker routed some 79% of the stolen funds through instant exchange FixedFloat using roughly 50 single-use addresses. ChangeNOW separately froze a six-figure sum after being contacted by Specter Investigations.

Around 282 ETH, roughly $542,000, across five addresses remains unmoved.

Within 24 hours, Coinsbuy refilled the drained wallets to within 0.05% of their pre-attack balances — behavior researchers say indicates the team does not believe private keys were compromised. The attack vector has not been established.

Coinsbuy told CoinDesk that the incident has been “contained” and that “all affected amounts have been covered in full by the company from its own reserves.”

The company added: “No client has borne any loss. The platform is stable and operating normally. Investigation is underway, and we cannot disclose further technical details at this stage.”

The incident adds to an increasingly costly year for the industry, which had already seen roughly $972 million stolen across the sector through late July.

Additional reporting by Ollie Acuna.

UPDATE, Aug 10, 12:43 UTC: Adds comment from Coinsbuy.

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