How much was lost in the SharedStake hack?

The SharedStake hack resulted in $500K in losses on June 24, 2021.

What attack technique was used in the SharedStake exploit?

The SharedStake exploit utilized Access Control. 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.

SharedStake Hack

TOTAL LOST $500K

Low Jun 24, 2021 Access Control

Affected Chain 2021 Incident surface

Recovered - No recovery reported

All-Time Rank #979 By amount stolen

Auditors 1 Prior security audit

Incident Overview

Some members of the SharedStake core team claimed that a SharedStake insider, who was given access to the bug report of critical timelock vulnerability by the SharedStake team, appears to have used the vulnerability to exploit the SharedStake contracts four times for approximately $500,000 on June 19 and June 23.

SharedStake rogue insider tests exploit on mainnet:

https://etherscan.io/tx/0x9400daa8…332c9f

SharedStake rogue insider exploits more timelocks on mainnet:

https://etherscan.io/tx/0x68dcf70e…6f38c5

https://etherscan.io/tx/0x466bca01…79cf39

https://etherscan.io/tx/0x2dff7aa6…328313

Some of the resulting funds have been swapped to a mix of USDC and vETH2.

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

Incident Report

Protocol / Project SharedStake

Date of Incident June 24, 2021

Attack Technique Access Control

Classification Yield Aggregator

Primary Source View Post-Mortem

Protocol Information

Protocol Type Liquid Staking

Affected Token SGT

Official Website www.sharedstake.org/

Protocol Twitter/X @SharedStakeOrg

Team Anonymous

Source Code Unverified

Market Context at Time of Hack

Token Categories

Ethereum Ecosystem BNB Chain Ecosystem

Protocol Links

GitHub Reddit

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 SharedStake'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

Audited by Audit Report 1 — still lost $500K. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to SharedStake, 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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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 Access Control Attacks examples →

Access Control Attacks

Sources & References

01
Source 1 https://medium.com/immunefi/sharedstake-insider-exploit-postmort…

Threat Assessment

Severity Level

LOW

Attack Vector Access Control
Root Cause Yield Aggregator
Year 2021

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