CVE-2018-13680 in LexitToken
Summary
by MITRE
The mintToken function of a smart contract implementation for LexitToken, 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 as CVE-2018-13680 represents a critical integer overflow flaw within the mintToken function of the LexitToken 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 pathway for malicious exploitation. The flaw specifically affects the token's ability to manage user balances, allowing an attacker with owner privileges to manipulate account balances arbitrarily. The vulnerability falls under the CWE-190 category of integer overflow and under CWE-699 for protection mechanism failures, highlighting both the mathematical and security control aspects of the flaw.
The technical implementation of this vulnerability occurs when the mintToken function processes token minting operations without proper bounds checking on the integer values involved in the balance calculations. In Ethereum smart contracts, integer overflows can occur when arithmetic operations exceed the maximum value that can be represented by the data type, causing the value to wrap around to zero or a negative number. When the owner invokes the mintToken function with malicious parameters, the integer overflow allows them to bypass normal balance validation mechanisms and directly set any user's token balance to an arbitrary value. This creates a fundamental breach in the contract's accounting system and undermines the integrity of the token distribution mechanism.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token economy and user trust in the LexitToken system. An attacker with owner access can inflate balances of specific users to create artificial token distribution patterns, manipulate market prices through artificial supply changes, or even create a scenario where the total supply calculation becomes invalid. The vulnerability effectively allows for unlimited token creation without proper authorization, as the overflow enables the owner to bypass the normal minting limits and controls that should govern token issuance. This represents a severe violation of the principle of least privilege and can lead to financial losses for users and potential market manipulation.
Mitigation strategies for CVE-2018-13680 require immediate implementation of proper input validation and integer overflow protection mechanisms within the smart contract code. The recommended approach involves implementing bounds checking on all integer operations, utilizing safe math libraries such as OpenZeppelin's SafeMath, and ensuring that all arithmetic operations include overflow and underflow protection. Additionally, the contract should implement proper access controls and audit trails to monitor owner activities, as the vulnerability specifically requires owner privileges to exploit. The remediation process should include thorough code review and testing procedures that validate all mathematical operations against potential overflow scenarios. Security practitioners should also consider implementing additional controls such as multi-signature requirements for owner operations and regular smart contract audits to prevent similar vulnerabilities from being introduced in future updates. The vulnerability demonstrates the critical importance of following secure coding practices in blockchain environments where financial assets are at stake, and aligns with ATT&CK techniques related to privilege escalation and resource hijacking within smart contract ecosystems.