CVE-2018-13779 in YLCToken
Summary
by MITRE
The mintToken function of a smart contract implementation for YLCToken, 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.
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Analysis
by VulDB Data Team • 02/27/2020
The vulnerability identified in CVE-2018-13779 represents a critical integer overflow flaw within the mintToken function of the YLCToken smart contract deployed on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types. The flaw allows the contract owner to manipulate token balances by creating an overflow condition that can result in arbitrary balance assignments to any user address within the system. Such a vulnerability fundamentally compromises the integrity of the token's accounting system and represents a severe security risk for all participants in the token ecosystem.
The technical implementation of this vulnerability occurs when the mintToken function processes token creation requests without proper boundary checking for integer values. When the contract attempts to increment a user's balance through the minting process, if the operation would exceed the maximum value that can be represented by the underlying integer type, the value wraps around to zero or a negative value due to the overflow behavior. This creates a scenario where the contract owner can precisely control the resulting balance of any user by manipulating the minting parameters. The vulnerability is classified under CWE-190 as an integer overflow condition, specifically involving signed integer overflow that can be exploited for unauthorized balance manipulation.
The operational impact of this vulnerability extends beyond simple financial manipulation to encompass potential systemic risks within the Ethereum token ecosystem. An attacker with owner privileges can artificially inflate or deflate user balances, potentially enabling fraudulent transactions, manipulation of token distribution, or even complete control over the token supply. This vulnerability undermines the fundamental trust assumptions of blockchain-based token systems, as it allows for arbitrary balance modification without any legitimate transactional justification. The implications are particularly severe for governance tokens or utility tokens where balance integrity is crucial for maintaining fair distribution and access control mechanisms.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security architecture improvements. The primary fix involves implementing proper input validation and boundary checking within the mintToken function to prevent integer overflow conditions from occurring. This includes using safe arithmetic libraries or explicit checks that verify operations before execution to ensure they remain within valid integer ranges. Additionally, implementing proper access controls and multi-signature requirements for contract ownership can reduce the risk of unauthorized exploitation. Organizations should also consider implementing comprehensive smart contract auditing processes and utilizing formal verification techniques to identify similar vulnerabilities before deployment. The remediation approach aligns with ATT&CK technique T1548.001 related to privilege escalation through contract ownership manipulation, emphasizing the importance of robust access control mechanisms and proper input validation in smart contract security.