Harmony Protocol stated this morning that it has discovered a theft worth around $100 million on the Horizon bridge.
The team claims to have started working with national authorities and forensic experts to identify the perpetrator and recover the stolen money.
The Horizon Bridge connects Harmony to the Ethereum network, the Binance Chain, and Bitcoin. Harmony is the bridge's operator and a layer-1 blockchain that uses proof-of-stake consensus.
According to reports, the hacking began at about 7:08 a.m. and continued until 7:26 a.m. (ET) this morning. During this time, the bridge processed 11 transactions for various tokens.
The most recent update notes that the hackers have also begun moving tokens to a new wallet to be exchanged for ETH on Uniswap, then returning the ETH to the original wallet.
Interestingly, a Twitter user going by the handle of @ apedev predicted the exploit in April of this year. "So, if two of the four multisig signers are compromised, we're looking at another nine-figure attack."
"Given recent events, it would be fascinating to hear some specifics from Harmony Protocol on how these EOAs are safeguarded," added the user. Ape Dev is the creator of Chainstride Capital, a crypto-focused venture firm.
Similarly, Vitalik Buterin raised key security issues about cross-chain bridges in the blockchain sector in a Reddit post back in January.
Furthermore, given that Meter's token bridge, Ronin Bridge, and Wormhole Bridge have all been hacked in recent months, there appears to be a need for improved security protocols.
According to appearances, multisigs have intrinsic security problems.