An unknown assailant inspired the atherium developers to roll the “private fix”, as the network was caught with technical issues during the pectra upgrade on the sepolia testnet.
One later ReportEtharium developer Marius van Der Wisden revealed that the attacker exploited an unseen “Edge case”, triggered errors by sending zero-token transfer for repeatedly deposited contracts, further complicated the distressed rollouts.
What happened?
On 5 March, the pectra upgrade became live on sepolia, but almost immediately, the developers began looking at the error messages on their Geth nodes, as well as mining with an increase in empty blocks.
According to the van der Wisden, the issue stems from the deposited contract that emits an unexpected event – a transfer phenomenon rather than the required deposits – which causes nodes to reject the transaction and produce empty blocks only.
The bug was connected to EIP-6110, in which all logs were required to be processed equally from the deposited contract.
The Geth team rolled out a fix, which would “ignore all the wrong log coming from the deposit contract,” but the developers allegedly ignored a specific age case in the ERC -20 standard.
“ERC20 does not forbid standard 0 tokens transfer, it allows anyone to transfer 0 tokens to another address, which would emit an incident to the 0 tokens,” Van der Wisden reported that a “attacker” repeatedly took advantage of this to deposit zero-token transfer.
This triggers the same error and caused the network to continue empty block mining.
Initially, the developers suspected that a reliable verification had made a mistake, but when investigated, he discovered the issue into a newly funded account from a public tap.
To prevent the attack, the developers needed to filter the transaction transactions with the contract submitted. However, he suspected that the attacker was monitoring his chat, which inspired him to roll a “private fix” to select the devops nodes that control about 10% of the network.
Once the fix was deployed, the nodes resumed the production of the full block, allowing the series to work by 14:00 UTC in general. After some blocks, the attacker’s transactions were successfully mined, confirming that all node operators updated.
Despite the disruption, the atherium “never lost final form”, and the issue was limited to sepolia, as its token-graded deposit contract was different from the contract atheram mannet deposits contract, according to the van der Wisden.
Nevertheless, the developers have decided to delay the pectra upgrade for further testing and debugging.
What is Ethereum’s Pactra upgrade?
The pectra fork is designed to increase ethe stacking, improve layer 2 scalability and expand network capacity. It introduces 11 Ethereum Improvement Proposal (EIP) and makes the first major upgrade since Denkun, which was live in March 2024.
As reported earlier by Crypto.news, the developers planned to deploy the pectra on the mannet by 8 April, provided both Holeski and Sepolia Testnet successfully fulfilled their upgrades.
The upgrade was first implemented on the Holesky Testnet on 24 February, where it also went into technical issues that were finalized.
