How much was lost in the ValueDefi hack?

The ValueDefi hack resulted in $7.0M in losses on November 14, 2020.

What attack technique was used in the ValueDefi exploit?

The ValueDefi exploit utilized Flashloan Price Oracle Attack / Flash Loan Attack. 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.

ValueDefi Hack

TOTAL LOST $7.0M

Medium Nov 14, 2020 Flashloan Price Oracle Attack / Flash Loan Attack ethereum

Affected Chain ethereum Incident surface

Recovered $2.0M 28.6% returned

All-Time Rank #371 By amount stolen

Auditors 1 Prior security audit

Incident Overview

Quick Summary

A Flash loan attack on ValueMultiVaultBank resulted in a loss of 5.4M DAI.

Details of the Exploit

The attacker initiated the exploit by flash loaning 80k ETH from Aave and flash swapping 166M DAI from Uniswap. They then swapped 80k for 31M USDT on Uniswap, deposited 25M DAI on ValueMultiVaultBank, and swapped 91M DAI to 90.2M USDC on Curve. The attacker then withdrew 33M 3CRV from ValueMultiVaultBank, swapped 17.3M USDC to 30.9M USDT on Curve, and removed liquidity with 33M 3CRV for 33.1M DAI on Curve.

They then repaid the flash swap and flash loan, transferred 2M DAI to Value Deployer, and finally transferred 5.4M DAI to their EOA.

Block Data Reference

The attacker's transaction:

https://etherscan.io/tx/0x46a03488…71150a

This is classified as a Flash Loans Attacks, Oracle Manipulation & Price Manipulation . Compare similar hacks →

Incident Report

Protocol / Project ValueDefi

Date of Incident November 14, 2020

Affected Chain(s) ethereum

Attack Technique Flashloan Price Oracle Attack / Flash Loan Attack

Classification Ecosystem / Exchange (DEX)

Primary Source View Post-Mortem

Protocol Information

Protocol Type Dexs

Affected Token VALUE

Smart Contract Language Solidity

Official Website valuedefi.io/

Protocol Twitter/X @value_defi

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 flashloan price oracle attack / flash loan attack and Solidity and EVM internals

Capital Required Flash loan capital (borrowed atomically, zero upfront cost)

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

Protocol Analysis Identification of the exploitable vulnerability in ValueDefi's contract logic - root cause: ecosystem / 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? Yes — skilled auditors routinely flag Flashloan Price Oracle Attack / Flash Loan Attack vulnerabilities in code review

Audited by Audit Report 1 — still lost $7.0M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to ValueDefi, these are the critical security checks that could have prevented this incident (November 2020).

Verify all logic paths related to Flashloan Price Oracle Attack / Flash Loan Attack are guarded by proper access controls and input validation - see the Flash Loans Attacks attack class for patterns
Audit oracle price feeds for manipulation risks - ensure time-weighted average prices (TWAPs) or multi-source aggregators are used, not spot prices
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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Funds Recovery

28.6%

Recovered

$2.0M

Net Loss

4998000

Security Audit History

Audit Report 1 Report

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Flash Loans Attacks examples →

Flash Loans Attacks Oracle Manipulation & Price Manipulation

Sources & References

01
Source 1 https://rekt.news/value-defi-rekt/
02
Reference https://twitter.com/FrankResearcher/status/1327649421492957184?s=20

Threat Assessment

Severity Level

MEDIUM

Attack Vector Flashloan Price Oracle Attack / Flash Loan Attack
Root Cause Ecosystem / Exchange (DEX)
Year 2020

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