CVE-2018-13498 in KAPAYcoin
Summary
by MITRE
The mintToken function of a smart contract implementation for KAPAYcoin, 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-2018-13498 represents a critical integer overflow flaw within the mintToken function of the KAPAYcoin Ethereum token smart contract implementation. This vulnerability resides in the contract's token minting mechanism where the owner can manipulate user balances through improper integer handling. The flaw allows an attacker with ownership privileges to set any user's token balance to an arbitrary value, effectively enabling unauthorized token distribution or manipulation. The vulnerability stems from inadequate input validation and overflow protection mechanisms within the smart contract's arithmetic operations.
The technical implementation of this vulnerability occurs when the mintToken function performs integer arithmetic without proper bounds checking or overflow detection. In Ethereum smart contracts, integer overflows can occur when mathematical operations exceed the maximum value that can be stored in a given data type, causing the value to wrap around to zero or negative numbers. This specific flaw in the KAPAYcoin contract allows the owner to bypass normal token minting restrictions and directly manipulate account balances through controlled overflow conditions. The vulnerability aligns with CWE-190, which describes integer overflow and underflow conditions, and represents a direct consequence of insufficient validation of user inputs and arithmetic operations within smart contract code.
The operational impact of this vulnerability is severe and multifaceted, affecting both the integrity and security of the KAPAYcoin ecosystem. An attacker with ownership access can manipulate token distributions to create unlimited tokens, potentially leading to massive dilution of existing token holders' value. The vulnerability also enables the creation of artificial balances that could be exploited for fraudulent activities, including manipulation of token prices, gaming of governance systems, or unauthorized transfers. Additionally, this flaw undermines the fundamental trust in the token's supply mechanism and could result in significant financial losses for users who hold KAPAYcoin tokens. The vulnerability's impact extends beyond immediate financial loss to include potential regulatory and compliance issues for the token issuer.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements in smart contract development practices. The primary fix involves implementing proper integer overflow protection mechanisms such as using safe math libraries or explicit bounds checking before arithmetic operations. Smart contract developers should adopt defensive programming practices including validation of all input parameters, implementation of overflow detection routines, and utilization of established security frameworks like OpenZeppelin's safe math libraries. Additionally, regular security audits and formal verification of smart contract code should be implemented to identify similar vulnerabilities before deployment. The remediation process should also include comprehensive testing of all arithmetic operations and thorough code review processes to prevent similar issues in future contract implementations. Organizations should consider implementing multi-signature ownership controls and time locks for critical contract functions to reduce the risk of unauthorized exploitation. This vulnerability demonstrates the importance of adhering to established security standards and best practices in blockchain development, as outlined in various security frameworks including those referenced in the ATT&CK framework for blockchain-based threats.