CVE-2018-13475 in VSCToken
Summary
by MITRE
The mintToken function of a smart contract implementation for VSCToken, 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 • 02/26/2020
The vulnerability identified as CVE-2018-13475 represents a critical integer overflow flaw within the mintToken function of the VSCToken smart contract implementation on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's token minting mechanism, creating a fundamental security weakness that directly impacts the contract's integrity and user asset management capabilities. The flaw specifically manifests when the mintToken function processes token creation requests, allowing unauthorized manipulation of user balances through mathematical overflow conditions.
The technical execution of this vulnerability occurs through the manipulation of integer arithmetic operations within the smart contract's mintToken function. When the contract attempts to increment token balances or perform arithmetic calculations involving token amounts, the absence of proper overflow checks enables attackers to exploit the mathematical limitations of fixed-size integer representations. This allows the contract owner to manipulate the balance of any user account to arbitrary values, effectively bypassing the normal token distribution and accounting mechanisms. The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic operations produce results that exceed the maximum value representable by the data type.
The operational impact of this vulnerability extends beyond simple financial manipulation to encompass complete contract compromise and potential systemic risks within the token ecosystem. An attacker with access to the contract owner privileges can arbitrarily inflate or deflate user balances, effectively creating unlimited tokens or zeroing out user holdings. This capability undermines the fundamental trust model of blockchain-based token systems and can result in significant financial losses for token holders. The vulnerability also creates potential for cascading effects within decentralized applications that depend on accurate token balances for their operations, as demonstrated by ATT&CK technique T1499.001, which covers resource hijacking through manipulation of token supply or balance.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and integer overflow protection mechanisms within the smart contract code. The recommended approach involves incorporating explicit overflow checks using modern Solidity practices such as SafeMath libraries or enabling the overflow protection features available in newer compiler versions. Contract developers should implement proper bounds checking and use of require statements to validate input parameters before performing any arithmetic operations. Additionally, regular security auditing and formal verification processes should be established to identify similar vulnerabilities in smart contract implementations. The fix must ensure that all arithmetic operations within the mintToken function and similar token management functions include proper overflow protection mechanisms, as outlined in the secure coding guidelines for smart contracts and the Ethereum Smart Contract Best Practices recommendations.