Saurik Awarded $2.1 Million Bounty for Ethereum Hack

Jay Freeman, better known as saurik, has been awarded a $2.1 million bounty for discovering a serious vulnerability in Ethereum scaling solution Optimism. Notably, saurik could have exploited the bug to access "infinite capital" but chose to disclose the vulnerability instead.

Saurik is best known for the creation of Cydia, a package manager for jailbroken iPhones. He has also developed multiple jailbreaks for Android and is one of the remaining founders of Orchid.

In a blog post, saurik describes the bug he's dubbed, "Unbridled Optimism".


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The bug presented here—which I dub "Unbridled Optimism"—can maybe be (crudely) modelled as a bug on the far side of a "bridge", but is actually a bug in the virtual machine that executes smart contracts on Optimism (an aforementioned L2 rollup).

Exploiting this enables the attacker to have access to an effectively unbounded number of tokens (aka, the IOUs) on the far side of the bridge. It is my contention that this is more dangerous than merely tricking the reserves into allowing a withdrawl.

With the ability to sneakily print IOUs (known on Optimism as OETH) on the other side of the bridge, you still can try to (slowly) withdraw money from the reserves, but now it will look like a legitimate transfer, making it easier to go unnoticed.

(And, in case you believe that "someone would notice if the total number of IOUs were different than the amount of money locked in the reserves", this bug actually was triggered 40 days ago—as I will point out later—and no alarm bells were raised.)


Further, with your unbounded supply of IOUs, you could go to every decentralized exchange running on the L2 and mess with their economies, buying up vast quantities of other tokens while devaluing the chain's own currency.

Using your access to infinite capital, you could further manipulate on-chain pricing oracles to leverage for other attacks; and, until someone finally realizes your money is counterfeit, arbitragers will flock to the network to sell you their assets.

This makes this bug capable of economic griefing attacks, wherein once someone notices—even if it is a mere hour later!—it might be "too late" to unravel what is and what isn't a legitimate transaction, calling into question the entire ledger.
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You can hit the link below to read saurik's full write up. You may also check out his upcoming talk about the bug at @EthereumDenver on Friday, February 18th at 9:40am MST on the Infinity Stage. The talk will be live streamed, likely at https://youtube.com/c/ETHDenver.

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