How much was lost in the Ethereum Yield hack?

The Ethereum Yield hack resulted in $1.1M in losses on February 11, 2021.

What attack technique was used in the Ethereum Yield exploit?

The Ethereum Yield exploit utilized Abandoned. 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.

Ethereum Yield Hack

TOTAL LOST $1.1M

Medium Feb 11, 2021 Abandoned ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #820 By amount stolen

Protocol Type Exit Scam/Abandoned Target category

Incident Overview

The project was holding token sales using 2 smart contracts:

https://etherscan.io/address/0x052cd742…f6bf5b#internaltx

https://etherscan.io/address/0x28a34597…553203#internaltx

The major and final Ether recipient, raised on the presale, was the Ethereum Yield deployer:

https://etherscan.io/tx/0xd4f0e4fd…d76450

https://etherscan.io/tx/0xbc4d09d8…8a4c01

https://etherscan.io/tx/0x45f56a33…f29e96

In total, the Ethereum Yield deployer received 3,100 ETH.

The contract deployer used 700 ETH to add the initial liquidity into the ETH / ETHY pair:

https://etherscan.io/tx/0x3a0f9586…fb75ce

This liquidity was locked till 01.01.2100 at:

https://etherscan.io/tx/0xaa6aab75…77a36b

The contract deployer used 1,000 ETH to add the initial liquidity into the ETH / ETHYS pair:

https://etherscan.io/tx/0xfed11e4b…0b0082

However, the liquidity wasn't locked and the contract deployer removed it multiple times at:

https://etherscan.io/tx/0xc9fe6fd4…b1dfd7

https://etherscan.io/tx/0x62d4cb45…91a7b5

https://etherscan.io/tx/0xf99ad612…8f1cfc

https://etherscan.io/tx/0x747add9e…fe8eb2

https://etherscan.io/tx/0xb55fb485…c3a77d

https://etherscan.io/tx/0x5eda7b6a…b004d1

https://etherscan.io/tx/0x0e09397f…bd80b7

The last pinned message in the official Telegram group says that the owner and developer left the team:

https://archive.is/fSGYW

Incident Report

Protocol / Project Ethereum Yield

Date of Incident February 11, 2021

Affected Chain(s) ethereum

Attack Technique Abandoned

Classification Token

Primary Source View Post-Mortem

Protocol Information

Protocol Type Exit Scam/Abandoned

Affected Token ETHY, ETHYS

Official Website ethereumyield.farm/

Protocol Twitter/X @EthereumYield

Market Context at Time of Hack

Token Categories

Ethereum Ecosystem Avalanche Ecosystem Solana Ecosystem Polygon Ecosystem BNB Chain Ecosystem

Protocol Links

GitHub

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 abandoned and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

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

Protocol Analysis Identification of the exploitable vulnerability in Ethereum Yield's contract logic - root cause: token

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 Abandoned audit checklist and test coverage

If you're auditing a protocol with similar architecture to Ethereum Yield, these are the critical security checks that could have prevented this incident (February 2021).

Verify all logic paths related to Abandoned 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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Sources & References

01
Source 1 https://ethereumyield.farm/

Threat Assessment

Severity Level

MEDIUM

Attack Vector Abandoned
Root Cause Token
Year 2021

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