Fireblocks Hack

TOTAL LOST $75.0M
High #99 All-Time Access Control

Summarize with AI

ChatGPT Perplexity Claude Grok
Affected Chain 2021 Incident surface
Recovered - No recovery reported
All-Time Rank #99 By amount stolen
Protocol Type Exploit/Access control Target category

Incident Overview

Quick Summary

Fireblocks company lost 75,000,000 $USD due to the negligence of the security engineer

Details of the Exploit

FireBlocks is an Israeli company that offers traditional financial institutes a seamless plug into the decentralized finance ecosystem and its customers. Cryptocurrency company StakeHound has filed a lawsuit against  Fireblocks, claiming that it lost NIS 245.5 million (approximately $75 million) worth of cryptocurrencies it was entrusted with. StakeHound claims that Fireblocks, a developer of secure cross-enterprise asset transfer infrastructure, was negligent and as a result, the funds have been lost and can not be recovered.

Fireblocks has denied any wrongdoing, claiming that: "The keys were generated by the client and stored outside the Fireblocks platform," and that "the customer did not store the backup with a third-party service provider per our guidelines."

This is classified as a Access Control Attacks . Compare similar hacks →

Incident Report

Protocol / Project Fireblocks
Date of Incident
Attack Technique Access Control
Classification CeFi
Primary Source View Post-Mortem #1 View Post-Mortem #2

Protocol Information

Protocol Type Exploit/Access control
Official Website www.fireblocks.com/
Protocol Twitter/X @FireblocksHQ
Team Public / Doxxed
Source Code Unverified

Market Context at Time of Hack

Token Categories
Mineable

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 Operational-security tradecraft (phishing, malware, leaked seed phrases, or insider access) to obtain treasury signing authority
Capital Required Minimal capital - only enough to cover gas while draining the compromised accounts
On-Chain Access Valid signing authority over the compromised wallets / multisig signers, allowing direct transfer of funds or stake authorization
Target Reconnaissance Identification of Fireblocks's high-value treasury accounts and the authority / multisig structure controlling them
Execution Speed Speed to drain the compromised accounts before the team detects the breach and revokes signing authority or freezes the assets
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 Access Control audit checklist and test coverage

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

  • Verify all logic paths related to Access Control 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

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