CVE-2018-13762 in Yumerium
Summary
by MITRE
The mintToken function of a smart contract implementation for Yumerium, 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 • 03/03/2020
The vulnerability identified in CVE-2018-13762 represents a critical integer overflow flaw within the mintToken function of the Yumerium Ethereum token smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's codebase, creating a fundamental security weakness that directly impacts the token's integrity and user funds. The flaw allows the contract owner to manipulate user balances arbitrarily, effectively bypassing the normal tokenomics and financial controls that should govern token distribution and ownership.
The technical execution of this vulnerability occurs through the mintToken function's failure to properly validate integer inputs during balance calculations. When the contract processes token minting operations, it performs arithmetic operations that can exceed the maximum value representable by the integer data types used in the smart contract. This overflow condition enables the contract owner to manipulate the internal accounting system and set any user's token balance to an arbitrary value, including potentially negative balances or values exceeding the total token supply. The vulnerability specifically relates to CWE-191, which describes integer underflow/overflow conditions, and can be classified under CWE-682, involving incorrect arithmetic operations that lead to unexpected program behavior.
The operational impact of this vulnerability extends beyond simple financial manipulation, creating significant risks for token holders and the broader ecosystem. An attacker with owner privileges can effectively drain token supply by creating excessive balances for malicious accounts or manipulate market dynamics by artificially inflating certain user balances. The vulnerability undermines the fundamental trust in the token's distribution mechanism and can lead to severe financial losses for legitimate token holders who may see their balances manipulated or their tokens diluted through unauthorized minting operations. This type of vulnerability directly impacts the security posture of the Ethereum blockchain ecosystem and demonstrates the critical importance of proper input validation in smart contract development.
Mitigation strategies for this vulnerability require immediate contract upgrades and comprehensive security auditing of existing smart contracts. The primary fix involves implementing proper integer overflow checks using modern Solidity practices such as SafeMath libraries or compiler versions that include built-in overflow protection. Additionally, contract owners should implement proper access controls and audit mechanisms to prevent unauthorized minting operations. Organizations should follow ATT&CK technique T1548.001, which addresses privilege escalation through code injection, by ensuring that only authorized entities can perform minting operations. The vulnerability highlights the necessity of adhering to security best practices such as those outlined in the Ethereum Smart Contract Security Best Practices guidelines, including thorough testing of arithmetic operations and comprehensive code reviews before deployment to production environments.