MetaMask’s disclosed security incident is facing closer onchain scrutiny after security researcher Kaden said 18 block rewards earned by MetaMask-operated validators were sent to the wrong fee recipient address and ended up at an account that had been funded through Tornado Cash. The diverted rewards totaled about 0.36 ETH. MetaMask has not confirmed that explanation or specified the nature of the incident.
In an Oct. 1 post on X, Kaden said 19 MetaMask validators had won block rewards and 18 of those rewards were not paid to the correct fee recipient. Instead, he said, the funds were sent to 0x98B9231de84334c1d48BA0b72CF13f92484924A3. His post read: "after some onchain sleuthing, i think this is what happened: 19 metamask validators had won block rewards, and 18 of the rewards were not paid to the correct fee recipient but instead to this tornado funded account."
18 reward payments arrived within about 4.5 hours
According to the report’s review of Blockscout records, the first inbound transaction to the cited address arrived at 18:27 Taipei time on Sept. 30, or 10:27 UTC. That transfer was about 0.098 ETH and came from Tornado Cash’s 0.1 ETH pool.
Less than two hours later, the same address began receiving block rewards. From 20:12 on Sept. 30 to 00:46 on Oct. 1 Taipei time, equivalent to 12:12 to 16:46 UTC, it received 18 payments totaling about 0.3614 ETH. Using the ETH reference price in the source report, about $2,684, that amount was worth roughly $970.
The report said the address received no new funds after that window and, as of 16:40 Taipei time on Oct. 1, had not sent out any funds.
10 of the validators were linked to Lido’s Consensys operator set
A comparison against beacon chain data showed that the 18 blocks were proposed by 18 different validators. Of those, 10 were Lido validators registered under the operator name "Consensys." The report noted that MetaMask’s staking business was previously known as Consensys Staking. The other eight had withdrawal addresses that did not belong to Lido.
As of 16:40 Taipei time on Oct. 1, none of the 18 validators had been slashed. Sixteen had already entered the exit queue, while two were still operating normally. In a separate post at 13:28 Taipei time, Kaden said three exploited validators had not yet exited.
Fee recipient and withdrawal address are separate settings
The report said Ethereum validators use two distinct address settings. The fee recipient receives transaction fees from proposed blocks as well as payments from block builders. The withdrawal address is where staked principal is sent after a validator exits.
That distinction matters. If only the fee recipient was changed, the attacker could divert block income without changing where the staked ETH principal goes. Kaden said that was why he believes the attacker likely obtained only around 0.36 ETH in rewards and may never have had the ability to withdraw the staked ETH itself.
MetaMask also said in its statement that its staking service is non-custodial and that the company does not manage customers’ withdrawal keys. Kaden added that it remains unclear how the attacker obtained signing authority. Depending on how that access was gained, he said, an attacker could intentionally cause validators to be slashed. Slashing destroys part of the stake and forces the validator to exit.
Kaden estimated 523,000 ETH were pulled in precautionary exits
Kaden estimated that precautionary exits tied to the incident involved around 17,000 validators and about 523,000 ETH, worth about $1.4 billion at the price used in the report. He also said 821 potentially affected validators had not exited, for reasons that were unclear. MetaMask has not confirmed those figures.
The report’s review of Lido’s public operator key data showed that no validator operated by Consensys under Lido was still in normal operation. As of 16:40 Taipei time on Oct. 1, 6,914 were in the exit process and 152 had already exited, totaling about 226,000 ETH. That accounted for more than 40% of Kaden’s estimate.
The same report said those validators were scheduled to finish exiting by the morning of Oct. 7 Taipei time, and none had been slashed.
Lido says stETH holders do not need to act
In a notice on its research forum, Lido said stETH holders do not need to take any action. It also said the protocol has more than 6,750 stETH in temporary reserves to help cushion operational disruption. At the reference ETH price used in the source report, that reserve was worth about $18 million.
The report also said BleepingComputer had asked MetaMask which part of its infrastructure was affected and whether any systems or data had been accessed. A MetaMask spokesperson referred the outlet to the public statement.
As of publication, MetaMask’s public position remained that it had found no immediate threat to MetaMask wallets and that it would provide updates when appropriate.