Share this article
Push to Cut Ethereum Network Fees Opens Funds-Draining Bug in Scaling Tool Arbitrum
The vulnerability would have allowed attackers to steal all ether deposits into Arbitrum Nitro.
Updated May 11, 2023, 5:26 p.m. Published Sep 21, 2022, 9:27 a.m.
The rush to find a way of lowering transaction costs on the Ethereum blockchain led developers behind scaling tool Arbitrum to miss a change in the latest version that would have allowed attackers to steal all funds sent to the network.
Arbitrum paid about 400 ether ($530,000) to the hacker who flagged the vulnerability.
STORY CONTINUES BELOW
The threat was found in the way transactions are submitted and processed on the network, through a tool known as a bridge, which allows users to transfer tokens between different blockchains. Attacks on bridges have become one of the biggest security threats in crypto, accounting for almost $1 billion stolen in the past year.
The white-hat hacker, known as 0xriptide, said in a Tuesday post that the vulnerability would affect any depositor attempting to bridge funds from Ethereum to Arbitrum Nitro, Arbitrum’s latest version.
My bug bounty write-up on a critical vulnerability I discovered on Arbitrum Nitro which allowed an attacker to steal all incoming ETH deposits to the L1->L2 bridge
— riptide (@0xriptide) September 20, 2022
https://t.co/WuR4RYUL3L@icodeblockchain @samiamka2 @Mudit__Gupta @0xRecruiter @BowTiedCrocodil @BowTiedDevil
0xriptide discovered that all incoming transactions through the bridge were sent via a message to the Arbitrum blockchain’s Delayed Inbox, which ran a check to see if the contracts behind those transactions were either in the completion process or had already been completed.
0xriptide found that slots meant for data storage were empty because a Nitro function meant to verify the transactions automatically changed the data. That would have allowed a bad actor to manipulate the bridge’s smart contract – accessible to everyone because it is open-source software – and set their own address as a receiver address.
A single line of code would have prevented anyone from making changes to the critical contract. It was, however, removed to allow for cheaper transactions and the vulnerability it created wasn't noticed, 0xriptide said.
“The largest deposit recorded on the inbox contract was 168,000 ETH (~$250mm) with typical total deposits in a 24-hour period ranging from ~1000 to ~5000 ETH.” This means the vulnerability could have potentially led to hundreds of millions of dollars in stolen funds.
CORRECTION (Sept. 22, 15:44 UTC): Corrects dollar value of ether in second paragraph. Original was a factor of 10 too small.
More For You
What to know:
- As of October 2025, GoPlus has generated $4.7M in total revenue across its product lines. The GoPlus App is the primary revenue driver, contributing $2.5M (approx. 53%), followed by the SafeToken Protocol at $1.7M.
- GoPlus Intelligence's Token Security API averaged 717 million monthly calls year-to-date in 2025 , with a peak of nearly 1 billion calls in February 2025. Total blockchain-level requests, including transaction simulations, averaged an additional 350 million per month.
- Since its January 2025 launch , the $GPS token has registered over $5B in total spot volume and $10B in derivatives volume in 2025. Monthly spot volume peaked in March 2025 at over $1.1B , while derivatives volume peaked the same month at over $4B.
More For You
ZKsync Lite to Shut Down in 2026 as Matter Labs Moves On
The company framed the move, happening in early 2026, as a planned sunset.
What to know:
- Matter Labs plans to deprecate ZKsync Lite, the first iteration of its Ethereum layer-2 network, the team said in a post on X over the weekend.
- The company framed the move, happening in early 2026, as a planned sunset for an early proof-of-concept that helped validate their zero-knowledge rollup design choices before newer systems went live.
Top Stories
