Exploit rsETH on Ethereum: a Safe wallet loses $7.73 million

A Safe wallet has lost approximately $7.73 million in rsETH within a few hours, falling victim to an rsETH exploit on Ethereum that leveraged a public function of the Uniswap v4 protocol to redirect funds to a pool specifically created by the attacker. The news, reported by the security firm Blockaid, brings attention to the risks associated with custom modules interacting with Uniswap v4's "hooks," the latest programmable version of the decentralized exchange protocol.

Key Points

• An unidentified user of a Safe wallet has suffered an estimated loss of $7.73 million in rsETH.
• The attack exploited a public multicall keeper to target a custom liquidity provider module on Uniswap v4.
• The funds were funneled into a hooked pool created by the attacker.
• The protocol involved is Uniswap version 4, which introduces programmable hooks in liquidity pools.

Loss of $7.73 million in rsETH due to an exploit on Ethereum

According to Blockaid, the victim was a user managing funds through a multisig Safe wallet, one of the most commonly used tools for the secure custody of crypto assets by individuals and institutions. Despite the typical protections of a multisig infrastructure, the attack managed to siphon off the equivalent of $7.73 million in rsETH, the liquid staking token associated with Ethereum.

Users and Assets Involved

The target of the attack remains anonymous, and Blockaid did not specify how the attacker was able to operate on a module linked to the wallet. The affected token, rsETH, represents a share of ETH staked through liquid staking protocols, a segment of decentralized finance that has attracted increasing capital in recent years due to its promise of immediate liquidity on otherwise locked assets.

Economic Impact of the Attack

The amount stolen, nearly $7.8 million, places this incident among the most significant exploits in recent months related to the Ethereum ecosystem. Why it matters: incidents like this target tools considered the safest, multisig wallets, demonstrating that custody security is insufficient if the modules or contracts they interact with are compromised upstream.

How the Attacker Operated: the Public Keeper Multicall

The attacker used a public multicall keeper, a function accessible to anyone, to target a custom liquidity provider module built on top of Uniswap v4.

The Targeted Liquidity Provider Module of Uniswap v4

Uniswap v4 introduced a hook-based architecture, additional contracts that allow developers to customize the behavior of liquidity pools. This flexibility, while paving the way for dynamic fee mechanisms or advanced strategies for liquidity providers, also multiplies the potential attack surfaces when modules are not designed with adequate access controls.

How the Keeper Multicall Works

In this specific case, the keeper multicall function was intended to automate routine operations on the liquidity provider module. The problem is that, being public, anyone could invoke it, including the attacker, who used it to force the redirection of assets to an unauthorized destination.

Funds Funneled into a Hooked Pool Created by the Attacker

Once the exploit was activated, the stolen funds were channeled into a hooked pool specifically built by the attacker within the same Uniswap v4 framework.

Details of the Hooked Pool

This pool, created specifically to absorb the stolen funds, exploited the same hook infrastructure that makes Uniswap v4 flexible for legitimate developers. In practice, the attacker replicated the protocol's logic to their advantage, turning a tool designed for liquidity customization into a channel for theft collection.

What It Means for Uniswap v4 Security

The incident comes at a time when Uniswap v4 continues to expand its ecosystem of custom hooks by third parties. Why it matters: the security of the entire framework depends not only on the base code of the protocol but also on the quality of the modules built on top of it by external developers. A single poorly designed module, like the one exploited in this attack, can be enough to drain millions of dollars, even when assets are held through tools considered robust like Safe multisig wallets.

FAQ

What was the economic impact of the exploit on Ethereum for the Safe wallet user?

The Safe wallet user lost approximately $7.73 million in rsETH due to the exploit.

Which protocol and module were targeted in the attack?

A custom liquidity provider module within the Uniswap version 4 protocol was hit.

How did the hacker execute the attack?

The attacker exploited a public function called keeper multicall to redirect the funds.

Where were the stolen funds directed during the attack?

The funds were funneled into a hooked pool specifically created by the attacker.