CVE-2018-13536 in ERC20_ICO
Summary
by MITRE
The mintToken function of a smart contract implementation for ERC20_ICO, 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 as CVE-2018-13536 represents a critical integer overflow flaw within the mintToken function of an Ethereum-based ERC20 token smart contract implementation. This vulnerability specifically affects ERC20_ICO token contracts and stems from improper input validation and arithmetic operations within the token minting mechanism. The flaw allows the contract owner to manipulate user balances arbitrarily, creating a fundamental breach in the token's integrity and potentially enabling unauthorized value manipulation.
The technical implementation of this vulnerability resides in the mintToken function where integer overflow conditions can be exploited through careful manipulation of input parameters. When the contract processes token minting operations, the arithmetic operations involved in balance calculations do not properly validate the maximum limits of integer values, allowing attackers to cause unsigned integer overflows. This overflow condition occurs when the addition or multiplication of token amounts exceeds the maximum representable value for the data type used, causing the value to wrap around to a smaller number. The vulnerability is classified under CWE-190 as an integer overflow or wraparound, which directly enables the malicious actor to manipulate the token supply and user balances beyond normal operational parameters.
The operational impact of this vulnerability extends far beyond simple balance manipulation, creating significant security implications for token holders and the overall ecosystem. An attacker with owner privileges can set any user's balance to an arbitrary value, potentially allowing for unlimited token creation, unauthorized distribution, or manipulation of token economics. This flaw undermines the fundamental principles of blockchain-based token systems where transparency and immutability are essential. The vulnerability can be exploited to create artificial scarcity, manipulate token prices, or enable unauthorized transfers that could result in financial losses for legitimate token holders. The attack vector requires only the contract owner's private key, making it particularly dangerous as it leverages existing administrative privileges rather than requiring complex external exploits.
Mitigation strategies for this vulnerability must address both the immediate technical flaw and the broader security architecture of the smart contract. The primary remediation involves implementing proper integer overflow checks using modern Solidity practices such as requiring SafeMath library operations or utilizing newer compiler versions that include built-in overflow protection. Contract developers should ensure that all arithmetic operations include validation checks before execution, particularly when dealing with user balances and token minting functions. Additionally, the principle of least privilege should be enforced by limiting administrative capabilities and implementing multi-signature requirements for critical operations. The vulnerability demonstrates the importance of adhering to established security frameworks and best practices in smart contract development, aligning with ATT&CK techniques that emphasize privilege escalation and resource manipulation within blockchain environments. Regular security audits and formal verification processes should be implemented to identify similar vulnerabilities in smart contract implementations and ensure compliance with industry standards for secure blockchain development.