Beanstalk Part 1

Summary

The use of pragma solidity =0.7.6; in smart contracts specifies the exact Solidity compiler version to be used for compilation. This practice is intended to ensure code compatibility and security by preventing the contract from being compiled with incompatible or potentially vulnerable compiler versions. However, specifying the version without a caret (^) or range operator can lead to the contract being compiled with a vulnerable version of Solidity if the specified version has known security issues. This could expose the contract to vulnerabilities that have been fixed in later versions.

Vulnerability Details

1. Create a smart contract in Solidity.

2. Specify the Solidity compiler version using the exact version syntax, e.g., pragma solidity =0.7.6;.

3. Compile the contract using the Hardhat or Truffle development environment.

4. Check if there are any known security vulnerabilities in the specified Solidity version.

Impact

If the specified Solidity version has known security vulnerabilities, deploying the contract could expose it to attacks that exploit these vulnerabilities. This could lead to loss of funds, unauthorized access to contract functions, or other malicious activities. The impact depends on the nature of the vulnerabilities and the specific use case of the contract.

Tools Used

Manual code audit with VS code

Recommendations

To mitigate this issue, it's recommended to use a caret (^) or range operator when specifying the Solidity version. This allows the contract to be compiled with the latest patch version within the specified minor version, reducing the risk of compiling with a vulnerable version. For example, changing pragma solidity =0.7.6; to pragma solidity ^0.7.6; would allow the contract to be compiled with any version in the 0.7.x series, including any patches that fix known vulnerabilities.

This change ensures that the contract is compiled with a version of Solidity that includes the latest security patches, reducing the risk of vulnerabilities.