Note: At the judges request here, this downgraded issue from the same warden has been included in this report for completeness.
https://github.com/code-423n4/2023-11-zetachain/blob/main/repos/node/x/crosschain/keeper/evm_hooks.go#L209
There are 2 ways to send ZETA token through the Zeta protocol.
The first (and probably the most used) use case is having a specific protection in order to prevent ZETA token to be transfered to the ERC20 ZETA token contract itself on the receiver external chain, as it doesnt make sense for this contract to owns any ZETA.
Unfortunatelly, the second mechanism doesnt provide such protection, which seems to warrant Medium severity.
ZETA token can be transfered to any EVM supported chain ZETA ERC20 token contract (so the ZETA ERC20 token contract itself would own those ZETA afterward), which seems to be something that should not be possible and breaking an invariant.
The following scenario would be possible with the lack of the missing protection.
I would recommend the team to put the same protection for the second mechanism, so its consistent and properly protected. Also validate DestinationAddress properly.
