ArkProject: NFT Bridge

Summary

A security audit on the StarklaneMessaging contract revealed issues with the mapping state management that could lead to unintended or inconsistent states.

Vulnerability Details

The contract uses a mapping (_autoWithdrawn) to track the state of messages. This setup can inadvertently lead to unintended or inconsistent states if not managed properly.

Affected Code:

POC (Proof of Concept)

Mappings in Solidity automatically return zero for any uninitialized key, which is implicitly treated as WITHDRAW_AUTO_NONE. Potential issues arise if proper state transitions are not enforced.

Scenario: Bob sends a message to Alice via the StarklaneMessaging contract. The state of the message must be tracked correctly to ensure it can only be consumed once.

1. Initial State (WITHDRAW_AUTO_NONE):

   bytes32 msgHash = keccak256(abi.encodePacked("Message from Bob to Alice"));

   ​

   Kopier kode

   By default, _autoWithdrawn mapping for msgHash returns zero, interpreted as WITHDRAW_AUTO_NONE.

2. Transition to Ready State (WITHDRAW_AUTO_READY):

   _autoWithdrawn[msgHash] = WITHDRAW_AUTO_READY;

   ​

   Kopier kode

   The msgHash state transitions from WITHDRAW_AUTO_NONE to WITHDRAW_AUTO_READY.

3. Message Consumption:

   if (_autoWithdrawn[msgHash] != WITHDRAW_AUTO_READY) {

   revert WithdrawMethodError();

   }

   _autoWithdrawn[msgHash] = WITHDRAW_AUTO_CONSUMED;

   ​

   Kopier kode

   The state of msgHash becomes WITHDRAW_AUTO_CONSUMED.

Impact

• Severity: Medium

• Replay Attacks: Potential for the same message being consumed multiple times.

• Incorrect State Consumption: Misinterpreted mapping states could cause improper management of message readiness and consumption.

Tools Used

• Manual Code Review

Recommendations

• Explicit Initialization: Ensure all mappings are explicitly initialized.

• State Transition Checks: Implement explicit state transition checks.

• Clear State Definitions: Utilize more granular state constants or enums.