CVE-2018-13770 in UltimateCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for UltimateCoin, 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-2018-13770 represents a critical integer overflow flaw within the mintToken function of the UltimateCoin Ethereum token smart contract implementation. This vulnerability resides in the core token functionality that governs the creation and distribution of new tokens within the blockchain ecosystem. The flaw allows the contract owner to manipulate token balances in ways that fundamentally compromise the integrity of the token economy. The integer overflow occurs when the mintToken function processes token minting operations without proper input validation or overflow checking mechanisms, creating a scenario where arithmetic operations can exceed the maximum representable value for the data type being used.
The technical exploitation of this vulnerability stems from the absence of proper boundary checks within the smart contract code, specifically in how the function handles large numerical inputs during token creation processes. When the owner invokes the mintToken function with carefully crafted parameters, the integer overflow allows them to manipulate the balance of any user account within the token system. This represents a fundamental failure in the contract's security architecture, as it grants the owner unprecedented control over the token distribution mechanism. The vulnerability directly maps to CWE-190, which identifies integer overflow and underflow conditions as a critical weakness in software systems, particularly in blockchain environments where such flaws can lead to complete financial system compromise.
The operational impact of this vulnerability extends far beyond simple balance manipulation, creating a severe threat to the entire token ecosystem and its users. An attacker with owner privileges can effectively mint unlimited tokens for themselves while simultaneously setting arbitrary balances for other users, potentially leading to massive wealth redistribution or complete token value destruction. This flaw undermines the fundamental trust that users place in the token system, as it allows for the creation of tokens without proper authorization or accounting. The vulnerability also creates potential for denial of service attacks where malicious actors could set user balances to zero or other arbitrary values, effectively freezing user funds or manipulating token economics. The implications for token governance and user financial security are profound, as this single flaw can compromise the entire economic model of the UltimateCoin system.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security architecture improvements. The primary solution involves implementing comprehensive input validation and boundary checking within the mintToken function to prevent integer overflow conditions. This includes using safe arithmetic operations that check for overflow conditions before performing calculations, as well as implementing proper access controls that limit the minting capabilities to authorized parties only. The contract should also incorporate comprehensive auditing mechanisms that track all token minting operations and maintain transparent records of balance changes. Additionally, developers should consider implementing the OpenZeppelin safe math libraries or similar secure arithmetic implementations that have been designed to prevent such overflow conditions. From a defensive perspective, this vulnerability aligns with ATT&CK technique T1059.006 for smart contract exploitation and highlights the importance of formal verification processes and security audits in blockchain development practices. The vulnerability serves as a critical reminder of the necessity for robust security controls in decentralized applications and the importance of adhering to established security frameworks like the OWASP Blockchain Top 10 when developing smart contracts.