Euro Token (SREUR)

[yuriy77k]

Audit request

• The smart contract is default ERC20 token "
• Based on Openzeppellin's official smart contract https://github.com/OpenZeppelin/openzeppelin-solidity/tree/master/contracts/token/ERC20

Deployed at https://etherscan.io/address/0x7a0e91c4204355e0a6bbf746dc0b7e32dfefdecf#code

Source code

https://github.com/SocialRemit/SOL

Disclosure policy

campmany@socialremit.com

Platform

ETH

Number of lines

168

[MrCrambo]

Auditing time 1 day.

[danbogd]

Auditing time: 2 days.

[yuriy77k]

@MrCrambo @danbogd assigned

[RideSolo]

Auditing time: 1 day.

[danbogd]

My report is finished.

[yuriy77k]

@RideSolo assigned

[yuriy77k]

Security Audit Report

1. Summary

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

Deployed at https://etherscan.io/address/0x7a0e91c4204355e0a6bbf746dc0b7e32dfefdecf#code

2. In scope

• SREUR.sol github commit hash 662ec938265d2756943f306266e378f4de46ae88.

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. Decrease Allowance

Severity: low

Description

decreaseAllowance throw in case if the value to be substracted is higher than the amount that is allowed, if the address owner wants to change the value allowed by reducing it and the spender withdraw a part of it before, the function might throw and give more chances for the spender to take the rest of the allowed value.

The value should be set to zero if the value to be subtracted is higher than the allowance.

Code snippet

https://github.com/RideSolo/SOL/blob/master/SREUR.sol#L236#L249

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/b1d4fbfd1c28ebb5feb372b8fc1836d4

https://gist.github.com/yuriy77k/2db527a987ddeee93e348ff886594be1

https://gist.github.com/yuriy77k/21aa160a08acef777e12850bc57a9e3b