Vulnerabilities > CVE-2018-10973 - Integer Overflow or Wraparound vulnerability in Koreashow Project Koreashow
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
NONE Integrity impact
HIGH Availability impact
NONE Summary
An integer overflow in the transferMulti function of a smart contract implementation for KoreaShow, an Ethereum ERC20 token, allows attackers to accomplish an unauthorized increase of digital assets via crafted _value parameters.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 1 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Forced Integer Overflow This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.
Seebug
| bulletinFamily | exploit |
| description | An integer overflow in the transferMulti function of a smart contract implementation for KoreaShow, an Ethereum ERC20 token, allows attackers to accomplish an unauthorized increase of digital assets via crafted _value parameters. ``` Let`s see where this issue is: function transferMulti(address[] _to, uint256[] _value) public returns (uint256 amount){ require(_to.length == _value.length); uint8 len = uint8(_to.length); for(uint8 j; j<len; j++){ amount += _value[j]; <------here, crafted _value can make amount overflow } require(balanceOf[msg.sender] >= amount); for(uint8 i; i<len; i++){ address _toI = _to[i]; uint256 _valueI = _value[i]; balanceOf[_toI] += _valueI; balanceOf[msg.sender] -= _valueI; Transfer(msg.sender, _toI, _valueI); } } ``` |
| id | SSV:97407 |
| last seen | 2018-07-09 |
| modified | 2018-07-09 |
| published | 2018-07-09 |
| reporter | Knownsec |
| title | erc20 contract KoreaShow bug(CVE-2018-10973) |