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Transfer() is used instead of Call() to transfer ETH #166

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code423n4 opened this issue Aug 3, 2022 · 2 comments
Closed

Transfer() is used instead of Call() to transfer ETH #166

code423n4 opened this issue Aug 3, 2022 · 2 comments
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bug Something isn't working duplicate This issue or pull request already exists QA (Quality Assurance) Assets are not at risk. State handling, function incorrect as to spec, issues with clarity, syntax

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@code423n4
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Lines of code

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L23
https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L51
https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L23
https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L51
https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/gas-service/AxelarGasService.sol#L128
https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/gas-service/AxelarGasService.sol#L144
https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/xc20/contracts/XC20Wrapper.sol#L63

Vulnerability details

The use of .transfer() or .send() to send ether is now considered bad practice as gas costs can change, which would break the code.

The transaction will fail inevitably when:

  • Target smart contract does not implement a payable function.
  • Target smart contract does implement a payable fallback which uses more than 2300 gas unit.
  • Target smart contract implements a payable fallback function that needs less than 2300 gas units but is called through proxy, raising the call’s gas usage above 2300.

Affected Codes

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L23

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L51

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L23

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/deposit-service/ReceiverImplementation.sol#L51

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/gas-service/AxelarGasService.sol#L128

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/contracts/gas-service/AxelarGasService.sol#L144

https://github.com/code-423n4/2022-07-axelar/blob/3729dd4aeff8dc2b8b9c3670a1c792c81fc60e7c/xc20/contracts/XC20Wrapper.sol#L63

Recommendation

Use call instead of transfer to send ether. And return value must be checked if sending ether is successful or not. make sure to check for reentrancy.
@code423n4 code423n4 added 2 (Med Risk) Assets not at direct risk, but function/availability of the protocol could be impacted or leak value bug Something isn't working labels Aug 3, 2022
code423n4 added a commit that referenced this issue Aug 3, 2022
@code423n4
xiaoming90 issue #166
7bd16a5
@GalloDaSballo
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See #203

@re1ro
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re1ro commented Aug 5, 2022 •
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Duplicate of #4

@re1ro re1ro added the duplicate This issue or pull request already exists label Aug 23, 2022
@re1ro re1ro marked this as a duplicate of #4 Aug 23, 2022
@re1ro re1ro closed this as completed Aug 23, 2022
@GalloDaSballo GalloDaSballo added QA (Quality Assurance) Assets are not at risk. State handling, function incorrect as to spec, issues with clarity, syntax and removed 2 (Med Risk) Assets not at direct risk, but function/availability of the protocol could be impacted or leak value labels Aug 28, 2022
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