How much was lost in the KoiSwap hack?

The KoiSwap hack resulted in $20K in losses on March 09, 2021.

What attack technique was used in the KoiSwap exploit?

The KoiSwap 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.

KoiSwap Hack

TOTAL LOST $20K

Low Mar 09, 2021 Rugpull binance

Affected Chain binance Incident surface

Recovered - No recovery reported

All-Time Rank #1886 By amount stolen

Protocol Type Dexs Target category

Incident Overview

The contract deployer added the initial liquidity at:

https://bscscan.com/tx/0xa5bad7ab…85c812

The liquidity was removed by the contract deployer at:

https://bscscan.com/tx/0x0c1e68fb…d6cfe3

In addition, the contract deployer sold tokens multiple time at:

https://explorer.bitquery.io/bsc/txs/calls?caller=0xc0acd947…a5d6c6&contract=0x05ff2b0d…608c7f

Incident Report

Protocol / Project KoiSwap

Date of Incident March 09, 2021

Affected Chain(s) binance

Attack Technique Rugpull

Classification Exchange (DEX)

Protocol Information

Protocol Type Dexs

Affected Token KOI

Protocol Twitter/X @TaikoSwap_

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 binance smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in KoiSwap's contract logic - root cause: exchange (dex)

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 KoiSwap, these are the critical security checks that could have prevented this incident (March 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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Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Exchange (DEX)
Year 2021

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