How much was lost in the Akropolis hack?

The Akropolis hack resulted in $2.0M in losses on November 12, 2020.

What attack technique was used in the Akropolis exploit?

The Akropolis exploit utilized Flashloan Reentrancy 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.

Akropolis Hack

TOTAL LOST $2.0M

Medium Nov 12, 2020 Flashloan Reentrancy Attack / Flash Loan Attack ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #647 By amount stolen

Auditors 1 Prior security audit

Incident Overview

The attacker created a token contract with the malicious logic, which called deposit again (reentrancy):

https://etherscan.io/address/0xe2307837…0bd62f

The attacker:

- created a fake token

- deposited the fake token

- got a callback to the fake token, deposited 25k DAI

- got credited for 25k DAI of deposits

- withdrew 50k DAI

The attacker address:

https://etherscan.io/address/0xe2307837…0bd62f

The stolen funds were transferred to some external wallet:

https://etherscan.io/tx/0xf1562356…2cb869

This is classified as a Flash Loans Attacks, Reentrancy . Compare similar hacks →

Incident Report

Protocol / Project Akropolis

Date of Incident November 12, 2020

Affected Chain(s) ethereum

Attack Technique Flashloan Reentrancy Attack / Flash Loan Attack

Classification Ecosystem / Yield Aggregator

Primary Source View Post-Mortem

Protocol Information

Protocol Type Yield

Affected Token AKRO

Smart Contract Language Solidity

Official Website www.akropolis.io/

Protocol Twitter/X @akropolisio

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 reentrancy 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 Akropolis's contract logic - root cause: ecosystem / 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? Yes — skilled auditors routinely flag Flashloan Reentrancy Attack / Flash Loan Attack vulnerabilities in code review

Audited by Audit Report 1 — still lost $2.0M. Prior audits don't guarantee safety, especially after post-audit code changes.

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

Verify all logic paths related to Flashloan Reentrancy Attack / Flash Loan Attack are guarded by proper access controls and input validation - see the Flash Loans Attacks attack class for patterns
Check that all state-changing functions follow the Checks-Effects-Interactions (CEI) pattern to prevent reentrancy and logic ordering bugs
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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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 Reentrancy

Sources & References

01
Source 1 https://rekt.news/akropolis-rekt/
02
Reference https://www.theblockcrypto.com/linked/84490/defi-project-akropol…

Threat Assessment

Severity Level

MEDIUM

Attack Vector Flashloan Reentrancy Attack / Flash Loan Attack
Root Cause Ecosystem / Yield Aggregator
Year 2020

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