CVE-2018-13664 in CWS
Summary
by MITRE
The mintToken function of a smart contract implementation for CWS, an Ethereum token, has an integer overflow that allows the owner of the contract to set the balance of an arbitrary user to any value.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/28/2020
The vulnerability identified in CVE-2018-13664 represents a critical integer overflow flaw within the mintToken function of the CWS Ethereum token smart contract implementation. This vulnerability falls under the CWE-190 category of integer overflow and under the ATT&CK technique T1059.001 for execution through smart contract manipulation. The flaw exists in the contract's logic where the mintToken function fails to properly validate or constrain integer values during token creation, creating an exploitable condition that allows the contract owner to manipulate user balances arbitrarily.
The technical exploitation of this vulnerability occurs when the contract owner invokes the mintToken function with malicious parameters that cause integer overflow conditions. In Ethereum smart contracts, integer overflows can occur when arithmetic operations exceed the maximum value that can be stored in the designated data type, typically resulting in wraparound behavior where the value resets to zero or a small positive number. This overflow condition in the mintToken function enables the attacker to manipulate the balance calculation in such a way that the target user's balance can be set to any desired value, including extremely large numbers or zero.
The operational impact of this vulnerability is severe and multifaceted for the affected Ethereum token ecosystem. The contract owner can manipulate user balances to either inflate accounts with excessive token amounts, potentially causing system instability or enabling unauthorized wealth accumulation, or to zero out user balances, effectively destroying user assets. This capability fundamentally undermines the trust and integrity of the token system, as it allows for arbitrary balance manipulation that can be used for financial theft, market manipulation, or system disruption. The vulnerability also poses risks to the broader Ethereum ecosystem as it demonstrates poor security practices in smart contract development that could be replicated in other token implementations.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The primary fix involves implementing proper integer overflow protection mechanisms in the smart contract code, including explicit bounds checking and validation of input parameters before performing arithmetic operations. Developers should utilize modern smart contract development frameworks and libraries that include built-in overflow protection features, such as OpenZeppelin's SafeMath library. Additionally, comprehensive code review processes should be established to identify similar vulnerabilities across all smart contract implementations. The contract owner should also implement proper access control measures and consider using multi-signature wallets for critical operations. Regular security audits and formal verification of smart contract code are essential practices to prevent similar vulnerabilities from being introduced in future implementations, as outlined in the security best practices recommended by the Ethereum Foundation and industry security standards.