Omni Bridge Hack

TOTAL LOST $272K
Low Other

Summarize with AI

ChatGPT Perplexity Claude Grok
Affected Chain 2022 Incident surface
Recovered - No recovery reported
All-Time Rank #1182 By amount stolen
Protocol Type Canonical Bridge Target category

Incident Overview

Quick Summary

Omni Bridge was hacked by exploiting a smart contract on the EthereumPoW chain. 200 $WETH was stolen by a replay attack and transferred through Mexc Global.

Details of the Exploit

Omni Bridge is a crosschain bridge. A replay attack was launched against Omni Bridge on the EthereumPoW chain, which resulted in a hacker exploiting 200 $WETH. The hacker was able to withdraw bridged funds from the both EthereumPoS and EthereumPoW chains because the OmniBridge contract failed to validate chainId before approving the transaction.

Block Data Reference

Attacker address:

https://etherscan.io/address/0x82faed2d…2dc677

OmniBridge address:

https://etherscan.io/address/0x8eb3b7d8…48e347

EthereumPoS transaction:

https://etherscan.io/tx/0xbddb0cc8…f8bdf5

EthereumPoW transaction:

https://www.oklink.com/en/ethw/tx/0x9c072551…861fb4

Incident Report

Protocol / Project Omni Bridge
Date of Incident
Attack Technique Other
Classification Bridge
Primary Source View Post-Mortem

Protocol Information

Protocol Type Canonical Bridge
Official Website omni.gnosischain.com/bridge
Protocol Twitter/X @Ronin_Network
Team Anonymous
Source Code Verified On-Chain

Market Context at Time of Hack

Token Categories
BNB Chain Ecosystem
Protocol Links

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Deep understanding of other and Solidity and EVM internals
Capital Required Seed capital to cover gas and initial position setup
On-Chain Access Ability to interact with smart contracts and deploy a custom exploit contract
Protocol Analysis Identification of the exploitable vulnerability in Omni Bridge's contract logic - root cause: bridge
Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block
Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Likely — with a thorough Other audit checklist and test coverage

If you're auditing a protocol with similar architecture to Omni Bridge, these are the critical security checks that could have prevented this incident (September 2022).

  • Verify all logic paths related to Other are guarded by proper access controls and input validation
  • Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.

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