How much was lost in the Exactly hack?

The Exactly hack resulted in $7.2M in losses on August 18, 2023.

What attack technique was used in the Exactly exploit?

The Exactly exploit utilized DebtManager Exploit. 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.

Exactly Hack

TOTAL LOST $7.2M

Medium Aug 18, 2023 DebtManager Exploit optimism

Affected Chain optimism Incident surface

Recovered - No recovery reported

All-Time Rank #368 By amount stolen

Auditors 1 Prior security audit

Incident Overview

Exactly is a decentralized, non-custodial, open-source protocol that provides an autonomous fixed and variable interest rate market, enabling users to frictionlessly exchange their assets' time value and complete the DeFi credit market.

Incident Report

Protocol / Project Exactly

Date of Incident August 18, 2023

Affected Chain(s) optimism

Attack Technique DebtManager Exploit

Classification Protocol Logic

Primary Source View Post-Mortem

Protocol Information

Protocol Type Lending

Smart Contract Language Solidity

Official Website exact.ly

Protocol Twitter/X @ExactlyProtocol

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 debtmanager exploit and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

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

Protocol Analysis Identification of the exploitable vulnerability in Exactly's contract logic - root cause: protocol logic

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? Likely — with a thorough DebtManager Exploit audit checklist and test coverage

Audited by Audit Report 1 — still lost $7.2M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Exactly, these are the critical security checks that could have prevented this incident (August 2023).

Verify all logic paths related to DebtManager Exploit 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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Security Audit History

Audit Report 1 Report

Sources & References

01
Source 1 https://twitter.com/DeDotFiSecurity/status/1692549866713407912

Threat Assessment

Severity Level

MEDIUM

Attack Vector DebtManager Exploit
Root Cause Protocol Logic
Year 2023

Learn to Prevent the Next Exactly

The Exactly hack is one of many attacks that skilled auditors are trained to detect before deployment. Master real exploit patterns and defense techniques with hands-on Web3 security training.

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