C0:7E:01:8C:93:EB:D0:FD:E3:CD:74:32:9F:AF:FA:6F:40:FD:8E:1C:05:E3:79:41:6C:77:CD:EF:3E:04:11:12: February 2022

Tasks

The assessment objectives and respective statuses are summarized in the following table:

Objective	Status
Audit any issues with Roles or Privileges within the contract and what the impact may be for any vulnerabilities due to privileges.	Objective met - suicide vulnerabilies identified pertaining to improper access control
Static Analysis issues	Objective met - ran slither on all contracts, identified over 14 vulnerabilities.
Compile and Deploy the contract set to a Local instance like Ganache to perform testing on the contract set. In particular the "Private-Sale.sol" contract may have some issues with protecting tokens. Show how it can be exploited.	Objective met - Reentry exploit code produced and deployed to Ganache environment.
Any other dynamic findings like fuzzing or formal verification and symbolic execution.	Objective not met - Did not perform dynamic testing using MithX due to commercial license required.

Summarized Findings

The following SmartContracts were subjected to static analysis using slither for common vulnerabilities:

Private-Sale.sol,
Halborn-Pool.sol,
MyTokens.sol

The vulnerabilities identified with business impact are:

Reentry (sev: high) - 3 instances found,
State-variable-shadowing (high),
Suicidal (sev: high) - 2 instances found,
Unchecked-transfer (sev: high),
Contract locking (sev: Med)

Note, all vulnerabilities with the impact of High & Medium are highlighted in yellow in the evidence section below.

There were 2 instances found of improper access control or rather known as a “suicide” vulnerability in MyToken.sol &

HalbornPool.sol respectively, it meant that a malicious attacker could self-destruct the contract. These vulnerabilities are

categorized as SWC-106 at https://swcregistry.io/docs/SWC-106

The following vulnerabilities with informational severity are:

Low level calls
Different Pragma Directives were used
Conformance to Solidity naming conventions
Dead Code
Unused State Variable
State Variable that Could be declared constant
Different pragma in used
Dead-Code
Incorrect versions of Solidity

A Proof of Concept (PoC) exploit was produced for Private-Sales.sol to drain the Bank of all Ether by exploiting a Reentry

vulnerability in lines 35-47. The PoC was built in remix and connected to the Ganache environment. The full Reentry exploit code (attacker.sol)

was also added to this report. It was noted that the following SmartContracts did not return any issues during analysis:

Migrations.sol,
HalbornInterface.sol

Evidences

Static Analysis: Private-Sale.sol

$ slither Private-Sale.sol

Reentrancy in PrivateSale.getRefund(uint256) (Private-Sale.sol#35-47):

External calls:

- (refunded) = msg.sender.call{value: quantity * TICKET}() (Private-Sale.sol#41)

State variables written after the call(s):

- purchasedTickets[msg.sender] -= quantity (Private-Sale.sol#45)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities

solc-0.8.10 is not recommended for deployment

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-versions-of-solidity

Low level call in PrivateSale.getRefund(uint256) (Private-Sale.sol#35-47):

- (refunded) = msg.sender.call{value: quantity * TICKET}() (Private-Sale.sol#41)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#low-level-calls

Static Analysis: HalbornPool.sol

$ slither HalbornPool.sol

Halborn._balances (MyToken.sol#12) shadows:

- ERC20._balances (openzeppelin/contracts/token/ERC20/ERC20.sol#36)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#state-variable-shadowing

Halborn.EmergencyDestroy(address) (MyToken.sol#30-33) allows anyone to destruct the contract

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#suicidal

DefiPool.deposit(uint256,address) (HalbornPool.sol#82-94) ignores return value by HAL.transferFrom(_sender,address(this),_amount) (HalbornPool.sol#87)

DefiPool.withdraw(address) (HalbornPool.sol#100-119) ignores return value by HAL.transfer(_user,userBalance[_user]) (HalbornPool.sol#117)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#unchecked-transfer

Contract locking ether found:

Contract DefiPool (HalbornPool.sol#20-134) has payable functions:

- HalbornInterface.deposit(uint256,address) (HalbornInterface.sol#6-7)

- HalbornInterface.withdraw(address) (HalbornInterface.sol#9-10)

- DefiPool.deposit(uint256,address) (HalbornPool.sol#82-94)

- DefiPool.withdraw(address) (HalbornPool.sol#100-119)

But does not have a function to withdraw the ether

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#contracts-that-lock-ether

Reentrancy in DefiPool.withdraw(address) (HalbornPool.sol#100-119):

External calls:

- HAL.transfer(_user,userBalance[_user]) (HalbornPool.sol#117)

State variables written after the call(s):

- userBalance[_user] = userBalance[_user] - initialUserBalance (HalbornPool.sol#118)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-1

Reentrancy in DefiPool.deposit(uint256,address) (HalbornPool.sol#82-94):

External calls:

- HAL.transferFrom(_sender,address(this),_amount) (HalbornPool.sol#87)

State variables written after the call(s):

- depositStart[msg.sender] = depositStart[msg.sender] + block.timestamp (HalbornPool.sol#91)

- userBalance[_sender] = userBalance[_sender] + _amount (HalbornPool.sol#89)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-2

Reentrancy in DefiPool.deposit(uint256,address) (HalbornPool.sol#82-94):

External calls:

- HAL.transferFrom(_sender,address(this),_amount) (HalbornPool.sol#87)

Event emitted after the call(s):

- Deposit(msg.sender,msg.value,block.timestamp) (HalbornPool.sol#93)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-3

Different versions of Solidity is used:

- Version used: ['^0.8.0', '^0.8.2']

- ^0.8.2 (HalbornInterface.sol#2)

- ^0.8.2 (HalbornPool.sol#2)

- ^0.8.2 (MyToken.sol#2)

- ^0.8.0 (openzeppelin/contracts/access/Ownable.sol#4)

- ^0.8.0 (openzeppelin/contracts/security/Pausable.sol#4)

- ^0.8.0 (openzeppelin/contracts/token/ERC20/ERC20.sol#4)

- ^0.8.0 (openzeppelin/contracts/token/ERC20/IERC20.sol#4)

- ^0.8.0 (openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol#4)

- ^0.8.0 (openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol#4)

- ^0.8.0 (openzeppelin/contracts/utils/Context.sol#4)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#different-pragma-directives-are-used

Context._msgData() (openzeppelin/contracts/utils/Context.sol#21-23) is never used and should be removed

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#dead-code

Pragma version^0.8.2 (HalbornInterface.sol#2) allows old versions

Pragma version^0.8.2 (HalbornPool.sol#2) allows old versions

Pragma version^0.8.2 (MyToken.sol#2) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/access/Ownable.sol#4) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/security/Pausable.sol#4) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/token/ERC20/ERC20.sol#4) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/token/ERC20/IERC20.sol#4) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol#4) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol#4) allows old versions

Pragma version^0.8.0 (openzeppelin/contracts/utils/Context.sol#4) allows old versions

solc-0.8.2 is not recommended for deployment

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-versions-of-solidity

Parameter DefiPool.deposit(uint256,address)._amount (HalbornPool.sol#82) is not in mixedCase

Parameter DefiPool.deposit(uint256,address)._sender (HalbornPool.sol#82) is not in mixedCase

Parameter DefiPool.withdraw(address)._user (HalbornPool.sol#100) is not in mixedCase

Function DefiPool.EmergencyWithraw(address,address,uint256) (HalbornPool.sol#131-133) is not in mixedCase

Variable DefiPool.HAL (HalbornPool.sol#44) is not in mixedCase

Function Halborn.EmergencyDestroy(address) (MyToken.sol#30-33) is not in mixedCase

Parameter Halborn.EmergencyDestroy(address)._to (MyToken.sol#30) is not in mixedCase

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#conformance-to-solidity-naming-conventions

Halborn.constructor() (MyToken.sol#13-15) uses literals with too many digits:

- _mint(msg.sender,10000000000 * 10 ** decimals()) (MyToken.sol#14)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#too-many-digits

DefiPool.allowed (HalbornPool.sol#27) is never used in DefiPool (HalbornPool.sol#20-134)

Halborn._balances (MyToken.sol#12) is never used in Halborn (MyToken.sol#9-34)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#unused-state-variable

transfer(address,uint256) should be declared external:

- DefiPool.transfer(address,uint256) (HalbornPool.sol#32-37)

deposit(uint256,address) should be declared external:

- DefiPool.deposit(uint256,address) (HalbornPool.sol#82-94)

withdraw(address) should be declared external:

- DefiPool.withdraw(address) (HalbornPool.sol#100-119)

getContractBalance() should be declared external:

- DefiPool.getContractBalance() (HalbornPool.sol#124-129)

EmergencyWithraw(address,address,uint256) should be declared external:

- DefiPool.EmergencyWithraw(address,address,uint256) (HalbornPool.sol#131-133)

pause() should be declared external:

- Halborn.pause() (MyToken.sol#16-18)

unpause() should be declared external:

- Halborn.unpause() (MyToken.sol#20-22)

mint(address,uint256) should be declared external:

- Halborn.mint(address,uint256) (MyToken.sol#24-26)

transferbyOwner(address,address,uint256) should be declared external:

- Halborn.transferbyOwner(address,address,uint256) (MyToken.sol#27-29)

EmergencyDestroy(address) should be declared external:

- Halborn.EmergencyDestroy(address) (MyToken.sol#30-33)

renounceOwnership() should be declared external:

- Ownable.renounceOwnership() (openzeppelin/contracts/access/Ownable.sol#54-56)

transferOwnership(address) should be declared external:

- Ownable.transferOwnership(address) (openzeppelin/contracts/access/Ownable.sol#62-65)

name() should be declared external:

- ERC20.name() (openzeppelin/contracts/token/ERC20/ERC20.sol#62-64)

symbol() should be declared external:

- ERC20.symbol() (openzeppelin/contracts/token/ERC20/ERC20.sol#70-72)

totalSupply() should be declared external:

- ERC20.totalSupply() (openzeppelin/contracts/token/ERC20/ERC20.sol#94-96)

balanceOf(address) should be declared external:

- ERC20.balanceOf(address) (openzeppelin/contracts/token/ERC20/ERC20.sol#101-103)

transfer(address,uint256) should be declared external:

- ERC20.transfer(address,uint256) (openzeppelin/contracts/token/ERC20/ERC20.sol#113-116)

approve(address,uint256) should be declared external:

- ERC20.approve(address,uint256) (openzeppelin/contracts/token/ERC20/ERC20.sol#132-135)

transferFrom(address,address,uint256) should be declared external:

- ERC20.transferFrom(address,address,uint256) (openzeppelin/contracts/token/ERC20/ERC20.sol#150-164)

increaseAllowance(address,uint256) should be declared external:

- ERC20.increaseAllowance(address,uint256) (openzeppelin/contracts/token/ERC20/ERC20.sol#178-181)

decreaseAllowance(address,uint256) should be declared external:

- ERC20.decreaseAllowance(address,uint256) (openzeppelin/contracts/token/ERC20/ERC20.sol#197-205)

burn(uint256) should be declared external:

- ERC20Burnable.burn(uint256) (openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol#20-22)

burnFrom(address,uint256) should be declared external:

- ERC20Burnable.burnFrom(address,uint256) (openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol#35-42)

Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#public-function-that-could-be-declared-external

HalbornPool.sol analyzed (11 contracts with 77 detectors), 54 result(s) found

Static Analysis: MyTokens.sol

$ slither MyToken.sol