Arbitrum Saved From Major ETH Loss by White Hat Hacker

An anonymous developer effectively saved Arbitrum from a $250 million loss

article-image

Blockworks Exclusive art by axel rangel

share

key takeaways

  • Arbitrum paid 400 ETH via ImmuneFi to white hat hacker
  • Arbitrum bridge bug was caused by bad initializers in the contract code

Another cryptocurrency vulnerability has been uncovered by a so-called white hat hacker, who found an exploitable bug in the bridge between Ethereum and Arbitrum Nitro.

The hacker, known as riptide on Twitter, outlined their discovery, which comes on the heels of an escalating series of hacks in the bridges that connect different blockchains, which collectively have been drained of hundreds of millions of dollars of predominantly user funds this year. 

Arbitrum, the layer-2 Ethereum scaling solution, paid riptide a bounty of 400 ether (ETH) as a reward via the bug bounty platform ImmuneFi.

The multi-million dollar vulnerability, as riptide called it, would have allowed an attacker to steal all incoming ether deposits from users attempting to bridge their assets between Ethereum layer-1 and layer-2 protocols to Arbitrum.

The initialization-related vulnerability, according to the white hat hacker, would have enabled any nefarious actor to impersonate a user and send the authentication message to the “sequencerInbox” function to execute the vulnerability. 

The largest deposit recorded on the inbox contract was 168,000 ETH, around $250 million, with average deposits ranging from 1,000 to 5,000 ETH in a 24-hour period, riptide said. 

Loading Tweet..

Another Twitter user, smartcontracts.eth, commented that “rollups are still heavily in development,” cautioning his followers to be careful on layer-2 protocols. A layer-2 refers to a mechanism built on top of a blockchain’s core layer, typically to increase scalability or speed, plus introduce additional features. 

A similar bug was seen in the token bridge Nomad’s smart contract, which cost the protocol  $190 million in cryptocurrency in the third-biggest cryptocurrency hack of the year.

Arbitrum recently launched Nitro exactly one year after the rollup’s now-defunct first iteration and ahead of the Merge.

Arbitrum NFTs

Additionally, Arbitrum plans to integrate with NFT marketplace OpenSea on Wednesday. 

A slew of NFT collections built on Arbitrum will be available to buy and sell directly on OpenSea.

OpenSea tweeted that creators would need to find their collections and set their creator fees directly. 

The marketplace recently added the royalties percentages front-and-center on a collection’s page.

Loading Tweet..

Start your day with top crypto insights from David Canellis and Katherine Ross. Subscribe to the Empire newsletter.

Explore the growing intersection between crypto, macroeconomics, policy and finance with Ben Strack, Casey Wagner and Felix Jauvin. Subscribe to the Forward Guidance newsletter.

Get alpha directly in your inbox with the 0xResearch newsletter — market highlights, charts, degen trade ideas, governance updates, and more.

The Lightspeed newsletter is all things Solana, in your inbox, every day. Subscribe to daily Solana news from Jack Kubinec and Jeff Albus.

Tags

Upcoming Events

Javits Center North | 445 11th Ave

Tues - Thurs, March 18 - 20, 2025

Blockworks’ Digital Asset Summit (DAS) will feature conversations between the builders, allocators, and legislators who will shape the trajectory of the digital asset ecosystem in the US and abroad.

Brooklyn, NY

TUES - THURS, JUNE 24 - 26, 2025

Permissionless IV serves as the definitive gathering for crypto’s technical founders, developers, and builders to come together and create the future.If you’re ready to shape the future of crypto, Permissionless IV is where it happens.

recent research

Research Report Templates.png

Research

An overview of the Base Ecosystem, with a focus on market leaders.

article-image

Although bitcoin hitting $120k by year’s end is looking unlikely

article-image

About 270 million HYPE has been claimed, valued around $7.6 billion

article-image

Stanford professors David Mazières and Dan Boneh will lead the lab alongside a cohort of graduate student researchers

article-image

With more companies holding BTC, bitcoin yielding strategies could become “a new corporate finance norm,” CoinShares posed

article-image

The proposal comes after Polygon governance considered a controversial use of bridged liquidity for yield

article-image

Can the community balance its decentralized ethos with the need for inclusivity and constructive debate?