How much was lost in the HSO hack?

The HSO hack resulted in $482K in losses on March 10, 2021.

What attack technique was used in the HSO exploit?

The HSO 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.

HSO Hack

TOTAL LOST $482K

Low Mar 10, 2021 Rugpull

Affected Chain 2021 Incident surface

Recovered $399K 82.7% returned

All-Time Rank #1021 By amount stolen

Protocol Type Exit Scam/Rugpull Target category

Incident Overview

On March 10, the Huobi Eco-Chain HECO oracle project HSO carried out an IDO and ran away 30,000 HT. The website and Telegram were unable to be reached. Later, 24823 HTs were recovered with the help of the HECO core code contribution team Star Lab, the HECO technical community, and the HECO White Hat Security Alliance.

Incident Report

Protocol / Project HSO

Date of Incident March 10, 2021

Attack Technique Rugpull

Classification Other

Primary Source View Post-Mortem

Protocol Information

Protocol Type Exit Scam/Rugpull

Affected Token HSO

Team Anonymous

Source Code Unverified

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 smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in HSO'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

If you're auditing a protocol with similar architecture to HSO, these are the critical security checks that could have prevented this incident (March 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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Funds Recovery

82.7%

Recovered

$399K

Net Loss

83351

Sources & References

01
Source 1 https://hacked.slowmist.io/

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Other
Year 2021

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