Summary

Older versions of Solidity, such as version 0.5.17, have known vulnerabilities that can significantly impact the security and functionality of smart contracts. These vulnerabilities range from minor issues to critical security flaws that could allow attackers to exploit contracts for unauthorized actions or financial gains.

Vulnerability Details

• Missing Revert on Overflow/Underflow:
  By default, in latest Solidity versions e.g 0.8.x, arithmetic operations that result in an overflow or underflow will cause the transaction to revert. This behavior is a response to the common vulnerability where arithmetic operations in smart contracts could wrap around in an unintended manner, leading to unexpected outcomes. However, Older Solidity versions e.g 0.5.17 lacks this feature.

Impact

This therefore may allow for overflows and underflows in arithmetic operations where SafeMath is not explicitely used in.

Tools Used

Manual Review

Recommendations

It is recommended to upgrade all existing code to be compatible with Solidity v0.8.x to benefit from these security enhancements.