CVE-2018-13637 in CikkaCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for CikkaCoin, 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 • 02/28/2020
The vulnerability identified in CVE-2018-13637 represents a critical integer overflow flaw within the mintToken function of the CikkaCoin Ethereum smart contract implementation. This vulnerability resides in the core token distribution mechanism and fundamentally compromises the contract's integrity by allowing unauthorized manipulation of user balances. The flaw manifests when the contract processes token minting operations, where arithmetic operations exceed the maximum value that can be stored in the designated data type, creating a condition where the balance calculation wraps around to an unintended value. Such overflow conditions are particularly dangerous in blockchain environments where financial assets are at stake and where the integrity of balance tracking directly impacts the entire ecosystem's trust model.
The technical implementation of this vulnerability stems from improper input validation and arithmetic handling within the mintToken function, which operates without adequate bounds checking or overflow protection mechanisms. When the owner invokes this function, the system fails to validate whether the intended balance update would cause an integer overflow, allowing the attacker to manipulate the calculation in such a way that the resulting balance becomes arbitrarily large or negative. This particular flaw aligns with CWE-191, which specifically addresses integer underflow and overflow conditions, and demonstrates how insufficient arithmetic validation can lead to complete control over contract state. The vulnerability operates at the contract level and affects all users whose balances may be manipulated through the compromised mintToken function, creating a fundamental breach of the token's economic model and user asset protection.
The operational impact of this vulnerability extends far beyond simple balance manipulation, as it enables the contract owner to effectively create unlimited tokens or assign excessive balances to specific addresses, potentially leading to complete economic disruption of the CikkaCoin ecosystem. An attacker could exploit this vulnerability to generate massive token holdings, dilute existing token value, or manipulate market dynamics by creating artificial supply conditions. The implications are severe enough to undermine the entire purpose of a token contract, which is to maintain accurate and secure balance tracking for all participants. This vulnerability creates a direct pathway for financial loss and system compromise, as the attacker gains the ability to manipulate token distribution and potentially drain the contract's resources or manipulate market conditions through artificial balance manipulation.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The recommended approach involves incorporating explicit bounds checking and using safe arithmetic libraries that automatically detect and prevent overflow conditions before they can be exploited. Developers should implement require statements that validate input parameters and ensure that arithmetic operations remain within acceptable ranges. Additionally, the contract should utilize modern Solidity versions that include built-in overflow protection features and employ comprehensive testing procedures including fuzz testing and formal verification to identify similar vulnerabilities. The remediation process must also include thorough code review practices that specifically examine all arithmetic operations and balance modifications to prevent recurrence of such issues. Organizations should consider implementing security audits and continuous monitoring systems to detect anomalous behavior patterns that might indicate exploitation attempts, while also ensuring proper access controls and owner permissions to minimize potential attack surfaces. This vulnerability serves as a critical reminder of the importance of robust security practices in blockchain development and the need for comprehensive testing before deployment of smart contracts to production environments.