CVE-2018-13776 in AppleToken
Summary
by MITRE
The mintToken function of a smart contract implementation for AppleToken, 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 • 03/03/2020
The vulnerability described in CVE-2018-13776 represents a critical integer overflow flaw within the mintToken function of AppleToken smart contract implementation on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types, creating a scenario where an attacker can manipulate token balances through malicious contract interactions. The flaw specifically affects the token contract's ability to properly manage user balances during the minting process, potentially enabling unauthorized balance manipulation by the contract owner.
The technical implementation of this vulnerability manifests when the mintToken function processes token minting operations without adequate overflow checks. In Ethereum smart contracts, integer overflow occurs when an arithmetic operation attempts to store a value that exceeds the maximum capacity of the data type being used. The AppleToken contract fails to implement proper bounds checking or overflow protection mechanisms, allowing the contract owner to exploit this weakness to set arbitrary user balances to any desired value. This vulnerability directly maps to CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a fundamental flaw in the contract's arithmetic handling capabilities.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token economy and user trust within the contract ecosystem. An attacker with owner privileges could artificially inflate user balances to create artificial scarcity, manipulate token distribution, or even execute financial fraud by setting balances to extremely high values. The consequences include potential loss of user funds, disruption of tokenomics, and erosion of confidence in the underlying smart contract infrastructure. This vulnerability also creates opportunities for sophisticated attacks that could leverage the manipulated balances to perform additional malicious operations within the Ethereum network.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The recommended approach involves utilizing established security libraries such as OpenZeppelin's SafeMath implementation that provides checked arithmetic operations to prevent overflow conditions. Additionally, comprehensive input validation should be implemented to verify that all balance updates fall within acceptable ranges before processing. The contract owner should also implement proper access controls and audit logging to monitor any suspicious mintToken function calls. From a strategic perspective, this vulnerability highlights the importance of adhering to established security standards and best practices in smart contract development, including regular security audits and formal verification processes to prevent similar issues in future implementations. Organizations should also consider implementing multi-signature wallet systems and time-locks for critical contract operations to reduce the risk of unauthorized exploitation.