Pizza DeFi Hack

TOTAL LOST $5.0M
Medium Arithmetic Error eos
Affected Chain eos Incident surface
Recovered - No recovery reported
All-Time Rank #490 By amount stolen
Year 2021 Incident year

Incident Report

Protocol / Project Pizza DeFi
Date of Incident
Affected Chain(s) eos
Attack Technique Arithmetic Error
Classification Token & Share Accounting

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 arithmetic error and Solidity and EVM internals
Capital Required Seed capital to cover gas and initial position setup
On-Chain Access Ability to interact with eos smart contracts and deploy a custom exploit contract
Protocol Analysis Identification of the exploitable vulnerability in Pizza DeFi's contract logic - root cause: token & share accounting
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 Arithmetic Error audit checklist and test coverage

If you're auditing a protocol with similar architecture to Pizza DeFi, these are the critical security checks that could have prevented this incident (December 2021).

  • Verify all logic paths related to Arithmetic Error 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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