CVE-2018-13561 in YourCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for YourCoin (ICO) (Contract Name: ETH033), 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-2018-13561 represents a critical integer overflow flaw within the mintToken function of the ETH033 smart contract implementation for the YourCoin ICO token on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic handling within the contract's codebase, specifically affecting how the contract manages token minting operations. The flaw allows the contract owner to manipulate user balances arbitrarily, fundamentally compromising the integrity of the token distribution mechanism.
The technical exploitation of this vulnerability occurs through the manipulation of integer arithmetic operations during token minting processes. When the mintToken function processes token creation requests, it fails to properly validate or constrain the input parameters, enabling the contract owner to submit malicious values that trigger integer overflow conditions. This overflow condition allows the owner to bypass normal balance limitations and directly set any user's token balance to an arbitrary value, effectively enabling unlimited token generation or manipulation of specific user accounts. The vulnerability is classified under CWE-190 as an integer overflow or wraparound, which occurs when an arithmetic operation produces a result that exceeds the maximum value that can be represented by the underlying data type.
The operational impact of this vulnerability extends beyond simple financial manipulation to encompass fundamental trust issues within the token ecosystem. The contract owner can arbitrarily inflate user balances, potentially enabling fraudulent activities such as creating unlimited supply tokens, manipulating market prices, or conducting unauthorized transfers. This vulnerability undermines the core principles of blockchain transparency and immutability by allowing the contract owner to modify user balances retroactively. The implications are particularly severe for an ICO token where user trust and fair distribution are paramount, as it creates opportunities for the owner to manipulate the token economy and potentially steal funds from other users.
Security mitigation strategies for this vulnerability require immediate contract upgrades and comprehensive code audits. The most effective remediation involves implementing proper integer overflow checks using modern Solidity practices such as the SafeMath library or explicit bounds checking before arithmetic operations. Additionally, the contract should remove or restrict owner privileges that allow arbitrary balance manipulation, implementing proper access controls and transparent minting procedures. The vulnerability demonstrates the importance of adhering to established security frameworks and principles, including those referenced in the ATT&CK framework for smart contract security, which emphasizes the need for proper input validation, arithmetic safety, and privilege management in decentralized applications. Organizations should implement comprehensive testing procedures including formal verification and automated security scanning to identify similar vulnerabilities before deployment.