In brief
- An attacker drained about 114 ETH, put at $305,000, from two Safe multisig wallets on Ethereum through a third-party Safe module called FlashLoopAdapter.
- Security firms SlowMist and Defimon traced the loss to a weak access check that a fake Safe contract could pass.
- Aave founder Stani Kulechov said the adapter is an external contract built on top of Aave and that Aave v3 was not affected.
An attacker drained two Safe multisig wallets on Ethereum on Oct. 1 by abusing FlashLoopAdapter, a third-party module that opens and closes leveraged Aave v3 positions. Monitoring service Defimon flagged the attack at 15:08 UTC and put the loss at $305,000.
Blockchain security firm SlowMist counted about 114.09 ETH stolen from the two wallets. Neither firm reported any loss inside Aave itself.
How the fake Safe got in
A Safe (formerly Gnosis Safe) module is a contract that a wallet’s owners allow to send transactions on the wallet’s behalf, without collecting owner signatures each time. That makes modules handy for automated strategies, and it makes their own security checks the only thing between an outsider and the funds.
According to SlowMist, FlashLoopAdapter’s open() and close() functions only asked the caller whether it had the module enabled. Any contract can answer “yes” to that question. The attacker deployed a fake Safe that always said yes, and the adapter treated it as a real customer.
The second flaw sat in the adapter’s swap step, which made a raw call to a router address and calldata picked by the caller. The attacker set the “router” to a victim Safe and the calldata to execTransactionFromModule, the Safe function that lets an enabled module move funds. Because the victim wallets had enabled FlashLoopAdapter, they carried out the order.
Where the money went
Defimon described the flow. The attacker took a WETH flash loan from Morpho, repaid one Safe’s 1,335 WETH debt on Aave, and then had that Safe withdraw 1,306 weETH of collateral to the attacker. A second Safe lost another 6.4 weETH. After swapping and repaying the flash loan, the attacker kept about 114.1 ETH. Defimon said both Safes had the same single owner.
So the large collateral figure is not the theft itself. Most of it went to closing out a leveraged position, and the gain was the equity left over once the debt was paid. Our guide to how crypto hacks happen covers why access-control bugs like this one keep showing up across exchanges and DeFi. The attack comes days after a fake bridge drained 766 ETH from DYORSWAP users, a case where the bait was a lookalike site rather than a code flaw.
Is Aave affected?
No, based on what has been published so far. “This is not Aave v3 contract, it’s third party external adapter built on top of Aave, zero effect on Aave v3,” Kulechov wrote on X. Both security alerts point at the adapter’s own code, not at Aave’s lending pools.
The team behind FlashLoopAdapter had not been named in the alerts or in Aave’s response at the time of writing, and we found no post-mortem from its developer. For Safe users, the incident is a reminder that every enabled module carries its own risk. The next things to watch are a statement from the adapter’s developer and whether the attacker’s address, which SlowMist published along with the exploit transaction, starts moving the funds.
