How much was lost in the Sonic Swap hack?

The Sonic Swap hack resulted in $824 in losses on December 21, 2020.

What attack technique was used in the Sonic Swap exploit?

The Sonic Swap 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.

Sonic Swap Hack

TOTAL LOST $824

Low Dec 21, 2020 Rugpull ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #2019 By amount stolen

Protocol Type Dexs Target category

Incident Overview

The contract deployer invoked mint() to generate 100,000 tokens onto his wallet:

https://etherscan.io/tx/0x7d8c79bb…eda13a

The contract deployer added initial liquidity at:

https://etherscan.io/tx/0x5f168df6…2c5626

The liquidity was removed by the contract deployer at:

https://etherscan.io/tx/0xcab94141…f2f693

Incident Report

Protocol / Project Sonic Swap

Date of Incident December 21, 2020

Affected Chain(s) ethereum

Attack Technique Rugpull

Classification Exchange (DEX)

Primary Source View Post-Mortem

Protocol Information

Protocol Type Dexs

Affected Token SNIC

Official Website sonicswap.io/

Protocol Twitter/X @SonicSwapIO

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 ethereum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Sonic Swap'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 Sonic Swap, these are the critical security checks that could have prevented this incident (December 2020).

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://twitter.com/CaptainJackAPE/status/1340930652321923073
02
Web Archive https://archive.ph/qkUL6

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Exchange (DEX)
Year 2020

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