ETH_BasicAttentionToken_audit_report.md

Basic Attention Token (BAT) audit report.

1. Summary

This document is a security audit report performed by danbogd, where Basic Attention Token (BAT) has been reviewed.

2. In scope

• BAToken.sol .

3. Findings

In total, 4 issues were reported including:

• 1 low severity issues.
• 3 minor observation.

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 into a function transfer(address _to, ... ) following code:

require( _to != address(this) );

3.2. Discrepancy with the ERC20 standard

Severity: minor observation

Description

In BAToken.sol, according to the ERC20 standard, the variable decimals should be declared as uint8.

Code snippet

https://gist.github.com/yuriy77k/9f8fcc78745cf81e3aff92da724b3d5c#file-batoken-sol-L93

3.3. Meaningless checks.

Severity: minor observation

Description

The msg.value == 0 condition check is meaningless in most cases.

Code snippet

https://gist.github.com/yuriy77k/9f8fcc78745cf81e3aff92da724b3d5c#file-batoken-sol-L136

3.4. Consider using latest version of solidity.

Severity: minor observation

Description

The contracts use solidity version 0.4.10. It is suggested to use the latest version and fix all compiler warnings that arise. Compiler version should be fixed to avoid any potential discrepancies in smart contract behavior caused by different versions of compiler.

4. Conclusion

The audited smart contract is safe to deploy. Some low severity issues were found.