Ethereum’s most notorious sandwich attacker just got compromised. Over the weekend, JaredfromSubway.eth — who spent years squeezing other traders for profit — lost at least $7.5 million in crypto to a trap disguised as a lucrative trade.
The attack struck in Ethereum’s mempool: the waiting room where on-chain trades go before they finalize. Integral to the way Ethereum works, its mempool is viewable by anyone – even rival traders. Savvy operators like JaredfromSubway.eth have long forged an edge with mempool intelligence. They front-run victims’ yet-to-finalize orders, pushing up the price for the user. Then, they back-run them too, creating an arbitrage sandwich.
This highly profitable trading strategy is controversial and unseemly, but also widespread. JaredfromSubway.eth has made tens of millions of dollars sandwiching other traders since 2023. His bot hunts for opportunities to extract value across DeFi, monitoring token pools for imbalances and inefficiencies, and, when it finds one, making a sandwich to capture some cash.
That’s what happened over the weekend. Jared’s bot spotted a series of pools that it could exploit. So it went through the normal motions – including granting spending approvals – needed for executing automated transactions quickly enough for the mempool.
But the smart contracts to which his bot granted spending approvals were actually honeypots. Their token trading pairs were illegitimate stooge assets; there wasn’t a real profit for Jared to extract. His bot didn’t register this. Over multiple transactions, it kept granting approvals to these malicious contracts — permissions that were never revoked. Once enough had accumulated, a tripwire smart contract activated and drained JaredfromSubway.eth of at least $7.5 million.
Stolen assets included ETH and millions of dollars in stablecoins. Keeping the assets in stablecoins presented a risk to the attacker; the stablecoins’ issuers could choose to freeze the funds. That may be why within minutes of acquiring the stablecoins, the attacker swapped them into ETH as well – shielding the stolen assets from an easy freeze.
Using Reactor, we can see that over the following days, the attacker split their ill-gotten gains across other wallets. This kicked off a chain of transfers leading into Tornado Cash, a tool that obfuscates the flow of funds.
The mechanics of this exploit offer a lesson for anyone transacting on-chain.
The attack worked because Jared’s bot granted token-spending approvals to smart contracts it never bothered to vet. Every day, ordinary DeFi users do the same thing. They approve contracts to spend their tokens – often granting unlimited permissions to code they’ve never read. Those approvals don’t expire. Each is a standing invitation for someone else to move your money. Jared’s bot had dozens of them pointing at malicious contracts, and it never noticed. Most wallets are no different.
Then there’s the counterparty problem. In traditional finance, you know who’s on the other side of a trade. On-chain, the counterparty is the smart contract itself – and if that contract is unverified, you’re essentially signing a deal you can’t read. Jared’s bot interacted with 66 fake contracts that mimicked legitimate tokens. A manual review of the code – or even a basic check of deployment history – might have flagged them. But the bot was optimized for speed. It skipped due diligence, and lost $7.5 million for it.
Revoke approvals you no longer need. Vet the contracts you interact with – check whether they’re verified on Etherscan, look at who deployed them. Be skeptical of new pools with no track record. Otherwise, you risk getting rolled.
What is a sandwich attack?
A sandwich attack is a predatory trading strategy where a bot monitors Ethereum’s mempool – the public waiting room for pending transactions – and spots a trade it can exploit. The bot front-runs the victim’s order with its own buy, pushing the price up, then lets the victim’s trade execute at the inflated price. Immediately after, the bot sells for a profit. The victim gets a worse deal; the bot pockets the difference. It’s called a sandwich because the victim’s trade is squeezed between the bot’s two orders – the bread on either side.
Who is JaredfromSubway.eth?
JaredfromSubway.eth is the pseudonymous operator of Ethereum’s most prolific sandwich bot, active since 2023. At its peak, the bot’s prolific sandwich activity cost traders an estimated $60 million a year. It was frequently the single largest gas consumer on the entire network.
How did the attack unfold?
An unknown attacker deployed 66 fake token contracts that mimicked legitimate assets like WETH, USDC, and USDT, and paired them with fraudulent liquidity pools. To Jared’s bot, these looked like easy sandwich targets. As the bot moved to exploit them, it granted token-spending approvals to the attacker’s contracts. But those approvals were never consumed or revoked. They stayed open, giving the attacker a means to move the bot’s real assets. Once enough approvals had accumulated, the attacker triggered a single coordinated transaction that swept approximately $7.5 million in ETH and stablecoins from the bot’s wallets. The stolen funds were quickly converted to ETH and sent through Tornado Cash.
How can I avoid getting hacked this way?
Revoke token approvals you no longer need. Vet the contracts you interact with before you sign anything. Check whether the contract is verified on Etherscan. Look at when it was deployed and by whom. Be wary of new, unaudited pools offering too-good-to-be-true trades – it may have been designed that way on purpose.
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