How much was lost in the Parity Multisig hack?

The Parity Multisig hack resulted in $150M in losses on November 09, 2017.

What attack technique was used in the Parity Multisig exploit?

The Parity Multisig exploit utilized Contract not initialized. 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.

Parity Multisig Hack

TOTAL LOST $150M

Critical #58 All-Time Nov 09, 2017 Contract not initialized ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #58 By amount stolen

Year 2017 Incident year

Incident Report

Protocol / Project Parity Multisig

Date of Incident November 09, 2017

Affected Chain(s) ethereum

Attack Technique Contract not initialized

Classification Protocol Logic

Primary Source View Post-Mortem

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 contract not initialized 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 Parity Multisig'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 Contract not initialized audit checklist and test coverage

If you're auditing a protocol with similar architecture to Parity Multisig, these are the critical security checks that could have prevented this incident (November 2017).

Verify all logic paths related to Contract not initialized are guarded by proper access controls and input validation - see the Access Control Attacks attack class for patterns
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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Related Attack Classes

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

See all Access Control Attacks examples →

Access Control Attacks

Sources & References

01
Source 1 https://blog.openzeppelin.com/on-the-parity-wallet-multisig-hack…

Threat Assessment

Severity Level

CRITICAL

Attack Vector Contract not initialized
Root Cause Protocol Logic
Year 2017

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