FreeCity

CertiKFiles named in the report

CertiK reviewed FreeCity on 26 Sep 2022: 23 findings, 0 critical; 9 marked fixed, 3 acknowledged, 11 open.

No open critical findings
Open the reportOpen FreeCity’s security record

Report hosted on skynet.certik.com.

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Findings23

Statuses are the security firm’s own, from its report.

SeverityOpenAcknowledgedFixed
Critical000
High031
Medium100
Low1008
HighCentralization Risks in `FreeCityGame_v2.sol` andAcknowledged

In the contract `FreeCityGame_v2` the role `DEFAULT_ADMIN_ROLE` has authority over the functions shown in the diagram below. Any compromise to the `DEFAULT_ADMIN_ROLE` account may allow the hacker to take advantage of this authority and do any of the following: - change the `OpenSea` address to a potentially malicious address - edit attributes of an NFT to their benefit - add or remove addresses he/she controls to the whitelist and gain privileged roles - update a token's royalty to their benefit ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_FreeCityGame_v2-FreeCityGame_v2-DEFAULT_ADMIN_ROLE.svg) In the contract `FreeCityGame_v2` the role `MINTER_ROLE` has authority over the functions shown in the diagram below. Any compromise to the `MINTER_ROLE` account may allow the hacker to take advantage of this authority and create, update, and open blind boxes, which contain mystery NFTs that they can then withdraw and keep for their benefit. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_FreeCityGame_v2-FreeCityGame_v2-MINTER_ROLE.svg) In the contract `FreeCityGame_v2` the role `whilteAddress` has authority over the functions shown in the diagram below. Any compromise to the `whilteAddress` account may allow the hacker to take advantage of this authority and mint NFTs to the blind boxes. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_FreeCityGame_v2-FreeCityGame_v2-whilteAddress.svg) ---- In the contract `MyToken` the role `_owner` has authority over the functions shown in the diagram below. Any compromise to the `_owner` account may allow the hacker to take advantage of this authority and mint an unlimited amount of tokens to an address he/she controls. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_MyToken-MyToken-_owner.svg)

HighCentralization Risks in `Proxy Contracts` and `ExAcknowledged

In the contract `AuthenticatedProxy` the role `user` has authority over the functions shown in the diagram below. Any compromise to the `user` account may allow the hacker to take advantage of this authority and create proxies from potentially malicious contract he/she controls, as well as revoke an address ProxyRegistry access. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_AuthenticatedProxy-AuthenticatedProxy-user.svg) ---- In the contract `FreeCityProxyRegistry` the role `_owner` has authority over the functions shown in the diagram below. Any compromise to the `_owner` account may allow the hacker to take advantage of this authority and grant an address he/she controls ProxyRegistry access. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_FreeCityProxyRegistry-FreeCityProxyRegistry-_owner.svg) ---- In the contract `ProxyRegistry` the role `_owner` has authority over the functions shown in the diagram below. Any compromise to the `_owner` account may allow the hacker to take advantage of this authority and revoke addresses ProxyRegistry access. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_ProxyRegistry-ProxyRegistry-_owner.svg) ---- In the contract `ExchangeCore` the role `_owner` has authority over the functions shown in the diagram below. Any compromise to the `_owner` account may allow the hacker to take advantage of this authority and change the protocol fee to an amount that can disrupt contract functionality, while also changing the protocol fee recipient to an address he/she controls in order to steal all the fees. ![](https://accelerator-tasks-prod.acc.corp.certik.com/70b8259c3d714d32a2f9fbcab0bc3086/diagrams/centralization_ExchangeCore-ExchangeCore-_owner.svg) ---- In the contract `OwnedUpgradeabilityProxy` the role `proxyOwner` has authority over the following functions: - `transferProxyOwnership()` - `upgradeTo()` - `upgradeToAndCall()` Any compromise to the `proxyOwner` account may allow the hacker to take advantage of this authority and transfer proxy ownership to an address he/she controls in order to upgrade the current implementation of the proxy and delegate call the new implementation for initialization, which can be a potentially malicious contract.

HighCentralized Control of Contract UpgradeAcknowledged

The cited contract is upgradeable, meaning the owner can upgrade the contract without the community's consent. If an attacker compromises the account, he/she can change the implementation of the contract and drain tokens from the contract.

Contracts in scope

No deployed address is recorded for this audit.

The report names a repository or files. Open the report to see its scope.

Repository and files the report names (22)

  • exchange/Exchange.sol
  • proxy/OwnableDelegateProxy.sol
  • exchange/SaleKindInterface.sol
  • exchange/SafeMath.sol
  • exchange/ERC20.sol
  • FreeCityGame_v2.sol
  • proxy/ProxyRegistry.sol
  • exchange/ERC20Basic.sol
  • proxy/FreeCityProxyRegistry.sol
  • exchange/TokenRecipient.sol
  • MyToken.sol
  • exchange/ArrayUtils.sol
  • proxy/OwnedUpgradeabilityProxy.sol
  • exchange/ERC721.sol
  • exchange/FreeCityExchange.sol
  • proxy/Proxy.sol
  • exchange/ReentrancyGuarded.sol
  • proxy/AuthenticatedProxy.sol
  • exchange/ERC721Instance.sol
  • proxy/TokenTransferProxy.sol
  • exchange/ExchangeCore.sol
  • proxy/OwnedUpgradeabilityStorage.sol

Part of FreeCity’s security record

FreeCity
Audits1 audit by 1 firmLast audit Sep 2022, by CertiK.
Critical findingsNo open critical findingsIn 1 report.
Open FreeCity’s security record

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