ChainLink Token Audit Report.

ETH_ChainLink_report.md

Security Audit Report

1. Summary

ChainLink Token smart contract security audit report performed by Callisto Security Audit Department

Token description:

Symbol      : LINK
Name        : ChainLink Token
Total supply: 1,000,000,000
Decimals    : 18 
Standard    : ERC677

2. In scope

• LinkToken.sol

3. Findings

In total, 2 issues were reported including:

• 2 low severity issues.

No critical security issues were found.

3.1. Known vulnerabilities of ERC-20 token

Severity: low

Description

1. It is possible to double withdrawal attack. More details here.

2. 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.

Recommendation

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

require( _to != address(this) );

3.2. No zero address checking

Severity: low

Description

In functions transfer(Line 81) and transferFrom(Line 118) there are no zero address checking.

Code snippet

https://gist.github.com/yuriy77k/c3a70d212a7f9ecda715252e45073158#file-linktoken-sol-L81

https://gist.github.com/yuriy77k/c3a70d212a7f9ecda715252e45073158#file-linktoken-sol-L118

4. Conclusion

The audited smart contract can be deployed. Only low severity issues were found during the audit.

5. Revealing audit reports

https://gist.github.com/yuriy77k/18f0b9562bfba4210550f251d91fe2ca

https://gist.github.com/yuriy77k/6ea910cccecf1c44f93b0551a474db51

https://gist.github.com/yuriy77k/6a6833c14f6a688eb142a00fd50630d9