Sparkn

Summary

The solidity fallback function is executed if none of the other functions match the function identifier or no data was provided with the function call. Only one unnamed function can be assigned to a contract and it is executed whenever the contract receives plain Ether without any data. To receive Ether and add it to the total balance of the contract, the fallback function must be marked payable. If no such function exists, the contract cannot receive Ether through regular transactions and will throw an exception.

Vulnerability Details

fallback() external { //<--------without payable
the same issue was also in Code4rena in the Zksync contest
https://github.com/code-423n4/2023-03-zksync-findings/issues/93
more about the fallback function
https://www.geeksforgeeks.org/solidity-fall-back-function/

Impact

fallback lack payable,will lead to differences from the mainnet, and many existing protocols may not work

Tools Used

Recommendations

add payable to the fallback()