A cross-chain bridge between BitBTC and the Ethereum layer-2 community Optimism has been in a position to keep away from a doubtlessly expensive exploit because of the work of an eagle-eyed Twitter person.
The customized cross-chain bridge presents a ramp for customers to ship belongings between Optimism’s community and BitAnt’s decentralized finance (DeFi) ecosystem, which includes yield services, nonfungible tokens (NFTs), swaps and the BitBTC token, in which 1 million BitBTC represents 1 Bitcoin (BTC).
The BitBTC bridge bug was highlighted by L2 network Abirtrum tech lead Lee Bousfield in an Oct. 18 Twitter post, warning that “BitBTC’s Optimism bridge is trivially vulnerable.”
Bousfield said he published the Tweet as the “team has ignored my messages, so I’m going to publish the critical exploit here.”
BitBTC’s Optimism bridge is trivially vulnerable. Their team has ignored my messages, so I’m going to publish the critical exploit here. https://t.co/onyN9SzBjt
— Lee Bousfield (@PlasmaPower0) October 18, 2022
In response to Bousfield, the BitBTC bridge had a bug that may permit an attacker to mint pretend 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 choose the L1Token tackle handed to the L1 facet of the bridge. Nonetheless, the L1 bridge utterly ignores what the L2 token was, and simply goes forward and mints the arbitrary L1 token!” he wrote, including that:
“Which means an attacker might deploy their very own token on Optimism, give themselves all the availability, and set that token’s L1 Token to the true BitBTC L1 tackle.”
For the bug to be exploited efficiently, Bousfield outlined that it might 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 principle, with an attacker making an attempt to withdraw “200 billion pretend 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 involved 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 presents to companions.
Fichter additionally famous that belongings “aside from BitBTC will not be in danger,” including that there was loads of “time and power positioned into the usual bridge” and inspired folks to make use of the usual bridge “until you understand what you’re doing.”
