Huobi Token (HT) security audit, conducted by the Callisto Network Security Department in July 2019.


Huobi Token (HT) Specificities




Audit Request

Audit Top 200 CoinMarketCap tokens.

Symbol      : HT
Name        : Huobi

Deployed at:

Source Code:

Disclosure policy




Number of lines:



Huobi Token (HT) Smart Contract Security Audit Report

Are Your Funds Safe?


1. In scope

2. Findings

In total, 3 issues were reported including:

  • 1 medium severity issues.
  • 2 low severity issues.

2.1. Known vulnerabilities of ERC-20 token

Severity: low.


  • It is possible to double withdrawal attack. More details here
  • Lack of transaction handling mechanism issue. WARNING! This is a very common issue and it already caused millions of dollars losses for lots of token users! More details here.


Add the following code to the transfer(_to address, ...) function:

require( _to != address(this) );

2.2. ERC20 Compliance: false instead of throw

Severity: medium.


From ERC-20 specification:

The function SHOULD throw if the _from account balance does not have enough tokens to spend.

But in this implementation it just returns false. This can lead to serious consequences. Because checking the return value of this function is rare.
For example, external contract may use this token contract as:

HTToken.transferFrom(recipient, this, value);
points[recipient] += value;

In this case recipient can get any value of points, but he may not have enough money and the code will succeed.

Code snippet:

  • transfer(), line 53
  • transferFrom(), line 63


The function SHOULD throw if the _from account balance does not have enough tokens to spend.

2.3. Zero address checking

Severity: low.


There is no zero address checking in functions transfer and transferFrom.

3. Conclusion

The audited smart contract has medium severity issue and can not be deployed. Reported issues must be fixed prior to the usage of this contract.

4. Revealing audit reports


Smart Contract Audits by Callisto Network.


Why Audit Smart Contracts?

Our Most Popular Audit Reports.

Trust the Blockchain, Audit the Smart Contracts.

Follow Callisto’s Security Department on Twitter to get our latest news and updates!