Атака на сеть Ethereum: после Fusaka валидаторы столкнулись с резким падением активности Headline: Attack on Ethereum Network: Validators Face Sharp Drop in Activity After Fusaka

Shortly after the deployment of Fusaka, a malfunction occurred in the widely-used consensus client Prysm, which disrupted the operation of a portion of Ethereum validators.

An error was identified in client version v7.0.0, which caused outdated blockchain states to be generated unnecessarily while processing old confirmations.

As explained by lead developer Terence Cao, the issue affected the proper functioning of nodes utilizing this client. Specialists proposed a temporary fix to disable the problematic feature.

Nevertheless, during epoch 411,448, the network’s key metrics significantly declined. Only 75% of nodes were signing the latest block headers, and consensus participation dropped to 74.7%. Ethereum was on the brink of a total failure, as there were less than nine percentage points remaining until complete halting of block finalization.

As of now (epoch 411,760), the network’s operation has normalized, with metrics nearly returning to pre-crisis levels:

Before the incident, these values consistently exceeded 99%.

The decrease in consensus participation roughly corresponds to the percentage of validators using the Prysm client. On December 3, it was estimated at 22.71%, whereas now it stands at 15.65%.

According to Ethereum’s consensus rules, the network loses finalization when validator voting participation drops below a critical threshold — two-thirds of the total staked ether.

In such a state, new blocks may be created, but the chain ceases to be irreversibly finalized, significantly increasing the risk of transaction history reorganizations. The loss of finalization would trigger a cascading failure throughout the ecosystem. Potential consequences could include:

This scenario is not merely hypothetical. In May 2023, Ethereum already faced finalization failures — twice in a single day. The cause was errors in data handling within the Prysm and Teku clients.

The current incident appeared relatively localized, but historically, the risk was much higher. In the fall of 2021, Prysm controlled over 66% of the nodes — meaning a single error in it could have paralyzed the entire network.

By January 2022, its share had reached 68.1%, placing the network in a vulnerable position.

Despite some progress, Ethereum remains far from a secure distribution of clients. A critical threshold of 33% for any single client is considered vital. Currently, Lighthouse dominates with a share of 52.55%.

«We narrowly avoided catastrophe by sheer luck. Had the error occurred in Lighthouse, the network could have lost finalization,» commented Ethereum expert Anthony Sassano.

Recall that at the beginning of September, a malfunction occurred in the execution-level Reth client from Paradigm. The bug led to the synchronization of nodes using this software being halted.