CVE-2018-13650 in BitmaxerToken
Summary
by MITRE
The mintToken function of a smart contract implementation for BitmaxerToken, 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.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/28/2020
The vulnerability identified as CVE-2018-13650 represents a critical integer overflow flaw within the mintToken function of the BitmaxerToken smart contract deployed on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling in the contract's code implementation, creating a fundamental security weakness that directly impacts the token's integrity and user fund safety. The flaw allows the contract owner to manipulate user balances arbitrarily, effectively bypassing the normal tokenomics and access control mechanisms that should govern token distribution and ownership.
The technical implementation of this vulnerability manifests through improper handling of integer arithmetic operations within the mintToken function, where the contract fails to validate whether the addition of new tokens to a user's balance would exceed the maximum value that can be represented by the underlying integer data type. This condition creates an exploitable scenario where the owner can manipulate the balance calculation through overflow arithmetic, enabling them to set any user's token balance to an arbitrary value. The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a classic example of how improper bounds checking can lead to severe financial consequences in smart contract environments.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial loss, contract integrity compromise, and systemic risk within the token ecosystem. An attacker with owner privileges could theoretically inflate user balances to excessive levels, potentially disrupting the token's economic model, or conversely reduce balances to zero, effectively freezing user funds. The vulnerability also creates opportunities for unauthorized value transfers and manipulation of token distribution mechanisms that undermine trust in the contract's operations. This flaw directly impacts the security posture of the BitmaxerToken and demonstrates the critical importance of proper input validation and arithmetic overflow protection in smart contract development practices.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive code auditing and security review processes for all smart contract deployments. The primary fix involves implementing proper bounds checking and overflow protection mechanisms within the mintToken function, ensuring that arithmetic operations are validated against maximum integer limits before execution. Additionally, contract owners should implement robust access control measures and consider using established smart contract frameworks that provide built-in overflow protection. The vulnerability highlights the necessity of adhering to security standards such as those outlined in the Ethereum Smart Contract Security Best Practices and emphasizes the importance of formal verification techniques. Organizations should also implement continuous monitoring and regular security assessments to detect similar vulnerabilities in existing contracts and prevent unauthorized manipulation of token balances. The incident underscores the critical need for developers to understand and properly implement integer arithmetic handling in blockchain environments, where financial consequences of such vulnerabilities can be severe and irreversible.