How much was lost in the YFFS Finance hack?

The YFFS Finance hack resulted in $130K in losses on December 11, 2020.

What attack technique was used in the YFFS Finance exploit?

The YFFS Finance 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.

YFFS Finance Hack

TOTAL LOST $130K

Low Dec 11, 2020 Rugpull ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #1436 By amount stolen

Protocol Type Dexs Target category

Incident Overview

According to reports around 300 ETH (~$130,000) was raised in a private pre-sale that took place over the span of under a minute.

The developer was aiming to deploy some of the ETH raised in the pre-sale into Uniswap, to allow speculators to bet on the coin. But when it came time to deploy these funds, the Telegram channel was deleted.

Incident Report

Protocol / Project YFFS Finance

Date of Incident December 11, 2020

Affected Chain(s) ethereum

Attack Technique Rugpull

Classification Yield Aggregator

Primary Source View Post-Mortem

Protocol Information

Protocol Type Dexs

Affected Token YFFS

Official Website yffs.finance/

Protocol Twitter/X @yffsfinance

Market Context at Time of Hack

Token Categories

BNB Chain Ecosystem

Protocol Links

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 YFFS Finance's contract logic - root cause: yield aggregator

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 YFFS Finance, 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://cryptoslate.com/in-one-day-a-total-of-1-2-million-worth-…
02
Web Archive https://web.archive.org/web/20201101120000/https://yffs.finance/

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Yield Aggregator
Year 2020

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