Submission Details
Severity:
Missing Zero-Address Check in `rescue` Function of `Rescuable` Contract
## Summary
The `rescue` function in the `Rescuable` contract allows the contract owner to rescue tokens or Ether from the contract. However, the function lacks a check to ensure that the `to` address is not the zero address (`address(0x0)`), which could lead to an unintended transfer of funds to the zero address, resulting in a loss of assets.
## Vulnerability Details
The `rescue` function is designed to transfer a specified amount of Ether or tokens to a given address. If the `token` address is `address(0x0)`, the function transfers Ether; otherwise, it transfers the specified token. However, the function does not validate that the `to` address is non-zero before performing the transfer. If `to` is mistakenly set to the zero address, the Ether or tokens could be irretrievably lost.
### Code Snippet
```solidity
function rescue(
address to,
address token,
uint256 amount
) external onlyOwner {
if (token == address(0x0)) {
payable(to).transfer(amount);
} else {
_safe_transfer(token, to, amount);
}
emit Rescue(to, token, amount);
}
```
## Impact
The primary impact of this issue is the potential loss of Ether or tokens if they are transferred to the zero address. This could happen due to a mistake in the input parameters or a malicious attempt to cause a denial of service by locking funds in an unreachable address. Such an event could result in financial loss for the contract owner or the contract itself.
## Tools Used
- Manual code review.
## Recommendations
To prevent the accidental transfer of funds to the zero address, it is recommended to add a validation check that ensures the `to` address is not `address(0x0)` before proceeding with the transfer.
### Suggested Fix
```solidity
function rescue(
address to,
address token,
uint256 amount
) external onlyOwner {
require(to != address(0x0), "Invalid recipient address");
if (token == address(0x0)) {
payable(to).transfer(amount);
} else {
_safe_transfer(token, to, amount);
}
emit Rescue(to, token, amount);
}
```
This change will ensure that the function only allows transfers to valid, non-zero addresses, preventing the accidental loss of funds.
## Severity
This issue is classified as **low** severity. While it does not present a direct security vulnerability, it can lead to the loss of funds if not addressed. Implementing a zero-address check will enhance the robustness and reliability of the contract, safeguarding assets from accidental or malicious transfers to the zero address.
Prize pool breakdown
Total prize
27,750 USDC
nSLOC
1,22923 USDC / LOC
25,000 USDC
2,750 USDC
2,250 USDC
Live
The contest is live. Earn rewards by submitting a finding.
Appeals
This is your time to appeal against judgements on your submissions.
Appeals Review
Appeals are being carefully reviewed by our judges.