A cross-chain bridge between BitBTC and the Ethereum layer-2 community Optimism has been capable of keep away from a probably pricey exploit due to the work of an eagle-eyed Twitter person.
The customized cross-chain bridge provides a ramp for customers to ship belongings between Optimism’s community and BitAnt’s decentralized finance (DeFi) ecosystem, which incorporates yield providers, NFTs, swaps and the BitBTC token, through which 1 million BitBTC represents 1 Bitcoin (BTC).
The BitBTC bridge bug was highlighted by L2 community Abirtrum tech lead Lee Bousfield in an Oct. 18 Twitter publish, warning that “BitBTC’s Optimism bridge is trivially weak.”
Bousfield mentioned he printed the Tweet because the “group has ignored my messages, so I will publish the crucial exploit right here.”
BitBTC’s Optimism bridge is trivially weak. Their group has ignored my messages, so I will publish the crucial exploit right here. https://t.co/onyN9SzBjt
— Lee Bousfield (@PlasmaPower0) October 18, 2022
In line with Bousfield, the BitBTC bridge had a bug that may permit an attacker to mint faux tokens on one facet of the bridge, and swap them for actual ones on the opposite.
“The Optimism L2 facet of the bridge permits you to withdraw any token, and it let’s that token decide the L1Token deal with handed to the L1 facet of the bridge. Nevertheless, the L1 bridge fully ignores what the L2 token was, and simply goes forward and mints the arbitrary L1 token!” he wrote, including that:
“Meaning an attacker might deploy their very own token on Optimism, give themselves all the provision, and set that token’s L1 Token to the actual BitBTC L1 deal with.”
For the bug to be exploited efficiently, Bousfield outlined that it could take “7 days to undergo, throughout which the L1 bridge might be mounted by way of an improve.”
Shortly after noting such, somebody went on to check that idea, with an attacker trying to withdraw “200 billion faux BitBTC from Optimism.”
The attacker reportedly claimed that it was merea check.
Bousfield additionally famous in a subsequent replace round 10 hours later that the bug had since been patched after he managed to get in touch with the BitBTC group.
Cointelegraph has reached out to the BitAnt group for affirmation on these particulars and can replace the story in the event that they reply.
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Optimism developer Kevin Fichter on Oct. 18 confirmed that the bug was on BitBTC’s facet of issues because it had used its personal customized bridge versus Optimism’s customary bridge it provides to companions.
Fichter additionally famous that belongings “aside from BitBTC usually are not in danger,” including that there was lots of “time and power positioned into the usual bridge” and inspired folks to make use of the usual bridge “except you recognize what you’re doing.”