How much was lost in the PolyButterfly hack?

The PolyButterfly hack resulted in $1.5M in losses on June 05, 2021.

What attack technique was used in the PolyButterfly exploit?

The PolyButterfly exploit utilized Rugpull. 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.

PolyButterfly Hack

TOTAL LOST $1.5M

Medium Jun 05, 2021 Rugpull polygon

Affected Chain polygon Incident surface

Recovered - No recovery reported

All-Time Rank #732 By amount stolen

Protocol Type Exit Scam/Rugpull Target category

Incident Overview

The contract deployer changed the ownership of the MasterChef contract to the malicious one:

https://polygonscan.com/tx/0x0d788bee…0556f0

The contract deployer removed funds from the MasterChef contract at:

https://polygonscan.com/tx/0x35a8ac07…76c563

Stolen funds were sold on ETH.

Incident Report

Protocol / Project PolyButterfly

Date of Incident June 05, 2021

Affected Chain(s) polygon

Attack Technique Rugpull

Classification Yield Aggregator,Exchange (DEX),Borrowing and Lending

Primary Source View Post-Mortem

Protocol Information

Protocol Type Exit Scam/Rugpull

Affected Token POLLEN

Official Website polybutterfly.finance/

Protocol Twitter/X @polybutterflyfi

Team Anonymous

Source Code Unverified

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 rugpull and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

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

Protocol Analysis Identification of the exploitable vulnerability in PolyButterfly's contract logic - root cause: yield aggregator,exchange (dex),borrowing and lending

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? Hard to catch — private key / OpSec failures are outside smart contract audit scope

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

Verify all logic paths related to Rugpull 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://azcoinnews.com/as-polygon-network-is-growing-scam-activi…

Threat Assessment

Severity Level

MEDIUM

Attack Vector Rugpull
Root Cause Yield Aggregator,Exchange (DEX),Borrowing and Lending
Year 2021

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