AFX Trade, a derivatives exchange that settles trades in USDC, was exploited for approximately $24.15 million on July 22 after an attacker targeted a bridge the protocol operates on Arbitrum, according to security firm Blockaid.
Blockaid said it detected the exploit at 21:30 UTC and published the transaction on Arbiscan. "The exploit was specific to a bridge that AFX operates," the firm wrote, adding that it is working with the Arbitrum team "to respond to the incident, to engage with the affected protocol, and to help them contain the stolen funds."
The attacker moved the funds to Ethereum and swapped them for 12,467 ETH at an average price of $1,937, according to onchain analytics account Lookonchain, which linked to the exploiter's address on Arkham.
AFX had not published a statement on its X account as of the time of writing. The Defiant reached out to AFX for comment.
Arbitrum Says Native Bridge Unaffected
Steven Goldfeder, co-founder of Arbitrum developer Offchain Labs, said the exploit did not compromise Arbitrum's own infrastructure.
"We're aware of a report of a bridge hack on Arbitrum and are investigating. We can confirm that the transaction in question originated from a third party protocol, and the Arbitrum native bridge has not been hacked or exploited in any way," Goldfeder wrote. "We will coordinate with the third party team and will report more details when we have them."
Nearly All Bridge Deposits Drained
The AFX bridge contract on Arbitrum held about $24.2 million in USDC before the attack, according to DefiLlama, meaning the exploit drained nearly all of the funds locked in the contract. Deposits in the bridge had grown from about $19.3 million in mid-June.
AFX, short for Anti-Fragile Exchange, describes itself as a sovereign Layer 1 blockchain built for decentralized derivatives, offering USDC-margined perpetuals with up to 100x leverage on crypto assets, equities, ETFs and commodities, according to its website. User deposits enter the protocol through the Arbitrum-based bridge contract that was targeted in the attack.
The attack follows a string of exploits targeting protocols on Arbitrum in July. On July 15, perpetuals exchange Ostium halted trading after an attacker manipulated its oracle system to drain up to $18 million in USDC from its liquidity vault.
Markets showed little immediate reaction. ETH was trading at about $1,928, roughly flat over 24 hours, while ARB was down 0.3% at $0.0806, according to CoinGecko. ARB set an all-time low of $0.0705 on June 26.