How much was lost in the Cool Cats hack?

The Cool Cats hack resulted in $21K in losses on September 14, 2021.

What attack technique was used in the Cool Cats exploit?

The Cool Cats 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.

Cool Cats Hack

TOTAL LOST $21K

Low Sep 14, 2021 Rugpull

Affected Chain 2021 Incident surface

Recovered - No recovery reported

All-Time Rank #1881 By amount stolen

Protocol Type Exit Scam/Rugpull Target category

Incident Overview

Quick Summary

Cool Cats (COOL20) project was rugpulled by deployer, removing liquidity worth 20,961 USD from UniSwap pool.

Details of the Exploit

COOL20 is an ERC20 token trading on UniSwap. On Sep 14, 2021, the deployer performed an exit scam by removing the entire liquidity from the UniSwap pool in a single transaction. The deployer removed 6.13 WETH, equivalent to approximately 20,961 USD, from the pool, leaving token holders with no liquidity to trade.

Block Data Reference

Deployer Address:

https://etherscan.io/address/0xF51D05c6…7621Ed

Liquidity Removal Transaction:

https://etherscan.io/tx/0x4cc63498…bf074d

Incident Report

Protocol / Project Cool Cats

Date of Incident September 14, 2021

Attack Technique Rugpull

Classification Token

Protocol Information

Protocol Type Exit Scam/Rugpull

Affected Token COOL20

Team Anonymous

Source Code Verified On-Chain

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 smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Cool Cats'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? Hard to catch — private key / OpSec failures are outside smart contract audit scope

If you're auditing a protocol with similar architecture to Cool Cats, these are the critical security checks that could have prevented this incident (September 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 Token
Year 2021

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