How much was lost in the Orion Protocol hack?

The Orion Protocol hack resulted in $3.0M in losses on February 02, 2023.

What attack technique was used in the Orion Protocol exploit?

The Orion Protocol exploit utilized Reentrancy. Understanding this attack vector is critical for smart contract auditors and developers building secure DeFi protocols.

How can developers prevent similar smart contract attacks?

Preventing smart contract hacks requires a combination of secure coding practices, thorough security audits, and understanding common attack vectors like reentrancy, oracle manipulation, and access control flaws. Smart Contract Hacking (SCH) provides hands-on training to help developers and auditors identify and prevent vulnerabilities before deployment.

Orion Protocol Hack

TOTAL LOST $3.0M

Medium Feb 02, 2023 Reentrancy

Affected Chain 2023 Incident surface

Recovered - No recovery reported

All-Time Rank #548 By amount stolen

Auditors 1 Prior security audit

Incident Overview

Quick Summary

Orion protocol was exploited via reentrancy vulnerability with a profit of about 3M $USD.

Details of the Exploit

Orion Protocol, a decentralized finance (DeFi) protocol that aggregates liquidity from centralized exchanges, recently suffered a reentrancy exploit that resulted in a loss of around $3 million in Ethereum (ETH) on Feb. 2. The attacker used manipulated swaps of flash loaned stablecoins and artificially deposited assets twice before withdrawing the inflated balance. The exploiter also created and used a fake token to double their balance before making off with the stolen loot. Orion CEO Alexey Koloskov said the damage was contained to an internal broker account, and user funds remained safe. Orion has addressed several issues, such as bug fixes and interface changes, and Rekt reported that the $3 million loss has motivated Orion to take a more controlled approach.

After the attack, 1100 ETH were sent through the tornado cash mixer and 657 ETH are still held in the attacker's balance on the Ethereum network.

Block Data Reference

Exploit TX:

https://bscscan.com/tx/0xfb153c57…2e2104

Exploiter addresses:

https://bscscan.com/address/0x837962b6…0484bd

https://bscscan.com/address/0x3dabf5e3…9e35f1

https://etherscan.io/address/0x3dabf5e3…9e35f1

Attacker contract:

https://bscscan.com/address/0x84452042…079b67

Example of tornado cash TX:

https://etherscan.io/tx/0xa3fd4f4c…d845cb

This is classified as a Reentrancy . Compare similar hacks →

Incident Report

Protocol / Project Orion Protocol

Date of Incident February 02, 2023

Attack Technique Reentrancy

Classification Other

Primary Source View Post-Mortem #1 View Post-Mortem #2 View Post-Mortem #3 View Post-Mortem #4 View Post-Mortem #5

Protocol Information

Protocol Type Derivatives

Official Website trade.orionprotocol.io/swap/ORN-USDT

Protocol Twitter/X @orion_protocol

Team Anonymous

Source Code Unverified

Market Context at Time of Hack

Token Categories

Collectibles & NFTs DeFi Ethereum Ecosystem Kenetic Capital Portfolio Pantera Capital Portfolio Base Ecosystem Made in America Binance Ecosystem

Protocol Links

GitHub Discord Reddit

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 reentrancy 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 Orion Protocol's contract logic - root cause: other

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? Yes — skilled auditors routinely flag Reentrancy vulnerabilities in code review

Audited by Certik — still lost $3.0M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Orion Protocol, these are the critical security checks that could have prevented this incident (February 2023).

Verify all logic paths related to Reentrancy are guarded by proper access controls and input validation - see the Reentrancy attack class for patterns
Check that all state-changing functions follow the Checks-Effects-Interactions (CEI) pattern to prevent reentrancy and logic ordering bugs
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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Security Audit History

Certik 2021-08-24 Report

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Reentrancy examples →

Reentrancy

Sources & References

01
Source 1 https://beincrypto.com/orion-protocol-post-mortem-details-3m-def…
02
Source 2 https://cryptoslate.com/orion-protocol-suffers-3m-hack-due-to-th…
03
Source 3 https://www.coindesk.com/business/2023/02/02/orion-protocol-lose…
04
Source 4 https://twitter.com/peckshield/status/1621342889522642944
05
Source 5 https://twitter.com/alexeykoloskov/status/1621269268959477763?s=…

Threat Assessment

Severity Level

MEDIUM

Attack Vector Reentrancy
Root Cause Other
Year 2023

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