Submitted by HE1M, also found by codehacker
When the governor proposes a diamondCut, governor must wait for upgradeNoticePeriod to be passed, or security council members have to approve the proposal to bypass the notice period, so that the governor can execute the proposal.
If the governors key is leaked and noticed by zkSync, the attacker must wait for the notice period to execute the already proposed diamondCut with the malicious _calldata based on the note below from zkSync, or to propose a new malicious diamondCut. For, both cases, the attacker loses time.
Since, there is a notice period (as zkSync noticed the key leakage, security council member will not approve the proposal, so bypassing the notice period is not possible), there is enough time for zkSync to apply security measures (pausing any deposit/withdraw, reporting in media to not execute any transaction in zkSync, and so on).
But, the attacker can be smarter, just before the proposal be executed by the governor (i.e. the notice period is passed or security council members approved it), the attacker executes the proposal earlier than governor with the malicious _calldata. In other words, the attacker front runs the governor.
Therefore, if zkSync notices the governors key leakage beforehand, there is enough time to protect the project. But, if zkSync does not notice the governors key leakage, the attacker can change the _calldata into a malicious one in the last moment so that it is not possible to protect the project.
Diamond.sol#L277
DiamondCut.sol#L46
_calldata should be included in the proposed diamondCut:DiamondCut.sol#L27.
Or, at least one of the security council members should approve the _calldata during execution of the proposal.
miladpiri (zkSync) confirmed and commented:
Alex the Entreprenerd (judge) commented:
