Lack of event emission after critical initialize() functions

[code423n4]

Handle

0xRajeev

Vulnerability details

Impact

Most contracts use initialize() functions instead of constructor given the delegatecall proxy pattern. While most of them emit an event in the critical initialize() functions to record the init parameters for off-chain monitoring and transparency reasons, Ticket.sol nor its base class ControlledToken.sol emit such an event in their initialize() functions.

Impact: These contracts are initialized but their critical init parameters (name, symbol, decimals and controller address) are not logged for any off-chain monitoring.

Proof of Concept

See similar Medium-severity Finding M01 in OpenZeppelin’s audit of UMA protocol: https://blog.openzeppelin.com/uma-audit-phase-4/

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/Ticket.sol#L24-L37

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/ControlledToken.sol#L22-L36

Examples of event emission:
https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/PrizePool.sol#L239-L243

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/YieldSourcePrizePool.sol#L47

Tools Used

Manual Analysis

Recommended Mitigation Steps

Emit an initialised event in Ticket.sol and ControlledToken.sol logging their init parameters.

[asselstine]

This is just event emission; it's severity is 0 (Non-critical).

[kamescg]

• https://github.com/pooltogether/pooltogether-pool-contracts/pull/new/fix/68
• add Initialize event to Ticket and ControlledToken pooltogether/pooltogether-pool-contracts#305

[dmvt]

I'm going to split the difference here. Events are important for various reasons. In this case, due to the proxy pattern, the creation of the contract in the initialize function happen at the same time, making it trivial for a user to go back and look at the initialization parameters in the creation transaction.