Wormhole Bridge Exploit Nets $326 Million Through Solana Signature Verification Flaw

On February 3, 2022, an attacker exploited Wormhole, the bridge connecting Solana and Ethereum, extracting assets valued at approximately $326 million. It was the second bridge exploit in under a week, following the earlier Qubit Finance incident, and it moved Wormhole into second place on Rekt's leaderboard of largest crypto losses.

Security researcher samczsun was the first to flag the problem publicly. Shortly after, the Wormhole team said the network was simply "down for maintenance" while it looked into a "potential exploit." The team then confirmed the incident directly, stating:

The wormhole network was exploited for 120k wETH. ETH will be added over the next hours to ensure wETH is backed 1:1.

Less than 24 hours later, Wormhole announced that the backing had been restored.

Credit for surfacing details of the exploit went to @samczsun, @gf_256, @ret2jazzy, and @kelvinfichter. The attacker's address was identified as 0x629e7da20197a5429d30da36e77d06cdf796b71a.

01How It Happened

At its core, the exploit tricked Wormhole's bridge contract into recognizing 120,000 ETH as having been deposited on Ethereum, which let the attacker mint an equivalent amount of wrapped whETH on Solana. The attack unfolded in four steps:

1. Reusing a SignatureSet from an earlier transaction, the attacker bypassed Wormhole's "guardians" — the validators responsible for confirming cross-chain transfers — by calling the bridge's verify_signatures function directly.
2. That function hands off actual verification of the SignatureSet to a separate Secp256k1 program. Because of a mismatch between the solana_program::sysvar::instructions precompile and the version of solana_program that Wormhole relied on, the contract failed to properly check the supplied address, allowing the attacker to submit one funded with only 0.1 ETH.
3. Using an account created hours earlier containing a single serialized instruction matching the Secp256k1 contract, the attacker forged the SignatureSet, called complete_wrapped, and fraudulently minted 120,000 whETH on Solana, relying on VAA verification generated in a prior transaction.
4. Across three transactions (one, two, three), 93,750 ETH was bridged back to Ethereum, where it has remained in the attacker's wallet. The remaining roughly 36,000 whETH was liquidated on Solana into USDC and SOL.

02The Bounty Offer

Certus One, the team behind Wormhole, sent an on-chain message directly to the attacker's address:

This is the Wormhole Deployer:

We noticed you were able to exploit the Solana VAA verification and mint tokens. We'd like to offer you a whitehat agreement, and present you a bug bounty of $10 million for exploit details, and returning the wETH you've minted. You can reach out to us at [email protected].

At $10 million, it was reported as the largest bug bounty offer seen at the time — a choice between keeping $10 million and walking away clean, or holding onto the full $326 million as a fugitive. The attacker never responded, and the funds were not returned.

Rekt separately contacted Wormhole's founders to ask how the team was able to replace such a large volume of ETH so quickly; after some delay, they would say only that a more detailed incident report was being prepared.

03Context

The exploit landed during an already difficult stretch for Solana, which had seen several outages and disruptions in the preceding months. In a January 2022 incident, Solend users were unable to top up collateral to avoid liquidation, with oracle issues contributing to further erroneous liquidations.

Coming a week after the Qubit Finance exploit and following the large-scale Poly Network attack the previous summer, the Wormhole incident was cited as reinforcing concerns Vitalik Buterin had previously raised about the security limitations of cross-chain bridge design. Whether the future of DeFi settles on cross-chain or multi-chain architecture remains an open question, but incidents like this underline the risks involved either way.