Thomas Daniels
Due to an unidentified user taking advantage of a network vulnerability, Ethereum’s most recent Pectra update on the Sepolia testnet experienced unanticipated disruptions. The problem arose from the mining of empty blocks caused by a misfired deposit contract event.
Core engineer Marius van der Wijden noted on March 8 that the upgrade, which was implemented at 7:29 a.m. on March 5, encountered immediate issues on Ethereum’s geth node. A deposit contract inadvertently emitting a transfer event rather than a deposit event was the primary cause.
Despite introducing a remedy, the team failed to consider an edge situation, which allowed an anonymous user to conduct zero-token transfers to the deposit address. The error was rekindled by this activity, which resulted in more empty block mining.
Van van Wijden first thought the transactions were the result of an unintentional validator error, but he later found out they came from a freshly loaded account that was accessed through a faucet. The ERC-20 token standard has a flaw that allows zero-value transfers, which the attacker took advantage of.
Developers believed the attacker was keeping an eye on internal conversations, so they secretly applied a special patch to a few DevOps nodes to combat the disruption. All nodes had been updated by 2:00 p.m., at which point the network returned to its regular operation.
Finalization was unaffected by the incident, and the problem was limited to Sepolia, where developers had opted for a token-gated deposit contract instead of the conventional mainnet contract.
Following a prior problem on the Holesky testnet on February 26, this represents the second significant setback for the Pectra upgrade. As a result, Ethereum developers have decided to delay Pectra’s complete rollout until after additional testing.
The update comes after Ethereum’s Dencun hard fork, which introduced better rollup efficiency and lower Layer-2 transaction costs on March 13, 2024. In the meantime, Hsiao-Wei Wang and Tomasz Stańczak have taken over as co-directors of the Ethereum Foundation, which has implemented a new leadership structure.
