Submission Details
Severity:
Signature replay attack on a different chain is possible
Summary
Signature replay attack is possible across different chains and cause loss of funds for the protocol.
Vulnerability Details
Since the message encoded by the user & then signed by the operator does not include a chainId, once the message has been signed, the message & the v, r, s params can be re-used by the user to withdraw funds on a different chain. The check here fails to protect against it.
Impact
Loss of funds for the protocol.
Tools Used
Manual inspection.
Recommendations
Include a chain id when operator is signing the message off-chain. Also, include it inside withdrawTokensToL1():
function withdrawTokensToL1(address to, uint256 amount, uint8 v, bytes32 r, bytes32 s) external {
+ uint256 chainID;
+ assembly {
+ chainID := chainid()
+ }
sendToL1(
v,
r,
s,
abi.encode(
address(token),
+ chainID,
0, // value
abi.encodeCall(IERC20.transferFrom, (address(vault), to, amount))
)
);
}
Rewards breakdown
nSLOC
99This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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