How much was lost in the Union Capital hack?

The Union Capital hack resulted in $500K in losses on February 10, 2021.

What attack technique was used in the Union Capital exploit?

The Union Capital exploit utilized Rugpull. 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.

Union Capital Hack

TOTAL LOST $500K

Low Feb 10, 2021 Rugpull ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #1003 By amount stolen

Auditors 1 Prior security audit

Incident Overview

The project was holding a fundraising event using TokenSale smart contract:

https://etherscan.io/address/0x87b5ef63…b86259#code

1000 ETH were raised on the token sale:

shorturl.at/svwF4

The Initial liquidity, using 500 ETH from the token sale was added:

https://etherscan.io/tx/0xfd1e40f9…da58a6

Tokens were bought for (10 + 10 + 20 + 100 + 50) ETH:

https://bloxy.info/tx/0x2e97605c…a7a895

https://bloxy.info/tx/0xc2a3c840…1865f6

https://bloxy.info/tx/0xd5fa35af…74f42d

https://bloxy.info/tx/0x2d3f3bb0…551165

https://bloxy.info/tx/0x12354f0d…6aa818

83.6 ETH were drained by removing the liquidity:

https://bloxy.info/txs/calls_from/0xca8b324d…e48b88?signature_id=1137786&smart_contract_address_bin=0x7a250d56…f2488d

https://bloxy.info/txs/calls_from/0xca8b324d…e48b88?signature_id=1102188&smart_contract_address_bin=0x7a250d56…f2488d

Incident Report

Protocol / Project Union Capital

Date of Incident February 10, 2021

Affected Chain(s) ethereum

Attack Technique Rugpull

Classification Other

Primary Source View Post-Mortem

Protocol Information

Protocol Type Lending

Affected Token UnicV2

Official Website unioncapital.io/

Protocol Twitter/X @unioncapital_io

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 rugpull 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 Union Capital's contract logic - root cause: other

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? Hard to catch — private key / OpSec failures are outside smart contract audit scope

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 Union Capital, these are the critical security checks that could have prevented this incident (February 2021).

Verify all logic paths related to Rugpull 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://unioncapital.io/
02
Web Archive https://web.archive.org/web/20201214064622/https://unioncapital.io/

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Other
Year 2021

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