CVE-2018-13568 in MktCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for MktCoin, 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-2018-13568 represents a critical integer overflow flaw within the mintToken function of the MktCoin Ethereum token smart contract implementation. This vulnerability resides in the core token functionality that allows for the creation and distribution of new tokens within the blockchain ecosystem. The integer overflow occurs when the smart contract processes token minting operations, specifically when handling large numerical values that exceed the maximum capacity of the data types used in the implementation. Such overflows typically arise from insufficient input validation and boundary checking mechanisms within the contract's code logic.
The technical exploitation of this vulnerability enables the contract owner to manipulate token balances through arbitrary user accounts by leveraging the integer overflow condition. When the mintToken function processes certain input values, it fails to properly validate that the resulting token balance would remain within acceptable numerical limits. This allows an attacker with owner privileges to craft specific inputs that cause the integer arithmetic to wrap around, resulting in unintended balance modifications. The vulnerability directly relates to CWE-190, which describes integer overflow and underflow conditions that can lead to unexpected behavior in software systems. The flaw operates at the fundamental level of the smart contract's arithmetic operations, where the lack of proper overflow detection creates a path for malicious balance manipulation.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token economy and user trust within the MktCoin ecosystem. An attacker with owner access can arbitrarily inflate or deflate user balances, effectively allowing for unauthorized token distribution or theft. This capability undermines the core principles of blockchain tokenomics and can lead to significant financial losses for token holders. The vulnerability creates a persistent threat vector that remains active as long as the contract remains deployed, since the integer overflow condition is inherent to the contract's implementation rather than being a temporary runtime issue. The attack surface is particularly concerning given that smart contract owners often have elevated privileges and may be compromised through various attack vectors including private key theft or governance attacks.
Mitigation strategies for this vulnerability must address both the immediate implementation flaw and broader security practices within the smart contract ecosystem. The primary remediation involves implementing comprehensive input validation and boundary checking mechanisms within the mintToken function to prevent integer overflow conditions. This includes using safe arithmetic libraries or explicit overflow detection before performing balance calculations, as recommended by the solidity best practices for secure smart contract development. Additionally, the contract should implement proper access controls and audit logging to track all minting operations and balance modifications. The vulnerability demonstrates the importance of adhering to established security frameworks and standards such as those outlined in the OWASP Smart Contract Security Verification Standard, which emphasizes the critical need for proper integer handling and overflow prevention in blockchain applications. Organizations should also consider implementing multi-signature wallets for contract ownership and regular security audits to identify similar vulnerabilities across their smart contract portfolios.