How much was lost in the Origin Protocol hack?

The Origin Protocol hack resulted in $8.0M in losses on November 17, 2020.

What attack technique was used in the Origin Protocol exploit?

The Origin Protocol exploit utilized Flashloan Reentrancy Attack / Flash Loan Attack. 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.

Origin Protocol Hack

TOTAL LOST $8.0M

Medium Nov 17, 2020 Flashloan Reentrancy Attack / Flash Loan Attack ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #344 By amount stolen

Protocol Type Dexs Target category

Incident Overview

Quick Summary

Origin Dollar (OUSD) was exploited due to a reentrancy attack, leading to an excess minting of OUSD and a loss of 70,000 ETH.

Details of the Exploit

The attacker borrowed 70,000 ETH from dYdX and exchanged a portion of it for USDT and DAI on Uniswap. They then used these stablecoins to mint OUSD from the Origin Protocol's vault. The attacker exploited a reentrancy vulnerability in the mint function of the OUSD contract to mint more OUSD than the equivalent stablecoin collateral in the vault.

This resulted in the attacker holding more OUSD than the total value in the vault. The attacker then exchanged the excess OUSD for USDT and DAI on Uniswap and SushiSwap, and withdrew the remaining stablecoins from the OUSD vault. Finally, the attacker returned the borrowed ETH to dYdX and transferred the stolen funds to their account.

Block Data Reference

The attacker's address:

https://etherscan.io/address/0xb77f7bba…079f83

The transaction behind the attack:

https://etherscan.io/tx/0xe1c76241…2a8401

The contract deployed at:

https://www.contract-library.com/contracts/Ethereum/0x47c3d843…0fdfe2

- 1,000,000 DAI was transferred to the attacker’s account

https://etherscan.io/tx/0x8c0459b6…84cd95

- 1,138,449.12 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0xae6bee28…83f6bb

- 531,688.76 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0xa990fe2c…26538f

- 248,059.48 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0xe95b4d3d…c14e55

- 543,305.34 USDT and 226,832.53 USDC were converted to ETH on Uniswap and transferred to the attacker’s account along with 1,128,244.36 DAI

https://etherscan.io/tx/0x49d59b45…f33aec

- 115,732.21 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0xcff80ddd…c089b4

- 53,994.89 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0x47e515d5…847343

- 300,000.00 OUSD was exchanged for 60,505.30 USDT on Uniswap

1,000,000.00 OUSD was exchanged for 187,152.67 USDT on SushiSwap

https://etherscan.io/tx/0x8a1907db…d76b15

- 25,191.33 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0xf14f4158…3633d9

- 300,000.00 OUSD was exchanged for 29,803.08 USDT on Uniswap

1,000,000.00 OUSD was exchanged for 98,401.29 USDT on SushiSwap

https://etherscan.io/tx/0x8eba96d3…3a29e7

- 11,616.27 OUSD was redeemed for a mix of stablecoins

https://etherscan.io/tx/0x9a133457…af0383

- 434,407.95 USDT and 24,443.08 USDC were converted to ETH on Uniswap and transferred to the attacker’s account along with 121,577.54 DAI

https://etherscan.io/tx/0x7db4e348…ffc45e

- 498,487.66 OUSD was transferred back to the deployer of the OUSD contract (Origin Protocol)

https://etherscan.io/tx/0x2c9d2029…ba211f

This is classified as a Flash Loans Attacks, Reentrancy . Compare similar hacks →

Incident Report

Protocol / Project Origin Protocol

Date of Incident November 17, 2020

Affected Chain(s) ethereum

Attack Technique Flashloan Reentrancy Attack / Flash Loan Attack

Classification Ecosystem / NFT,Stablecoin

Primary Source View Post-Mortem

Protocol Information

Protocol Type Dexs

Affected Token OUSD

Smart Contract Language Solidity

Official Website www.originprotocol.com/

Protocol Twitter/X @code423n4

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 flashloan reentrancy attack / flash loan attack and Solidity and EVM internals

Capital Required Flash loan capital (borrowed atomically, zero upfront cost)

On-Chain Access Ability to interact with ethereum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Origin Protocol's contract logic - root cause: ecosystem / nft,stablecoin

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 Flashloan Reentrancy Attack / Flash Loan Attack vulnerabilities in code review

If you're auditing a protocol with similar architecture to Origin Protocol, these are the critical security checks that could have prevented this incident (November 2020).

Verify all logic paths related to Flashloan Reentrancy Attack / Flash Loan Attack are guarded by proper access controls and input validation - see the Flash Loans Attacks 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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Related Attack Classes

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

See all Flash Loans Attacks examples →

Flash Loans Attacks Reentrancy

Sources & References

01
Source 1 https://rekt.news/hack-epidemic/
02
Reference https://blog.originprotocol.com/urgent-ousd-has-hacked-and-there…

Threat Assessment

Severity Level

MEDIUM

Attack Vector Flashloan Reentrancy Attack / Flash Loan Attack
Root Cause Ecosystem / NFT,Stablecoin
Year 2020

Learn to Prevent the Next Origin Protocol

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