CVE-2018-13604 in wellieat
Summary
by MITRE
The mintToken function of a smart contract implementation for wellieat, 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-2018-13604 represents a critical integer overflow flaw within the mintToken function of a smart contract implementation for the wellieat Ethereum token. This vulnerability stems from improper input validation and arithmetic handling within the contract's code, creating a scenario where the contract owner can manipulate user balances arbitrarily. The flaw manifests when the mintToken function processes token minting operations without adequate overflow checks, allowing malicious or authorized contract owners to manipulate the total supply and individual user balances through carefully crafted inputs.
The technical implementation of this vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions in software systems. In the context of Ethereum smart contracts, this vulnerability enables the contract owner to exploit the underlying integer arithmetic by providing inputs that cause the balance calculations to wrap around to unintended values. The mintToken function likely performs operations such as balance += amount or totalSupply += amount without proper bounds checking, making it susceptible to overflow scenarios where large values exceed the maximum representable integer limits. This type of vulnerability is particularly dangerous in blockchain environments because the immutable nature of smart contracts means that once deployed with such flaws, they cannot be easily corrected without creating new contracts.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token ecosystem and user funds. An attacker with contract owner privileges can artificially inflate user balances, create artificial scarcity, or even drain funds from other users by manipulating the token supply calculations. The implications are severe because the wellieat token's functionality depends on accurate balance tracking and supply management. This vulnerability undermines the fundamental trust in the token's integrity and could lead to financial losses for users who hold tokens in the affected contract. The impact is amplified by the fact that Ethereum smart contracts operate in a trustless environment where users must rely on the code's correctness, making such vulnerabilities particularly damaging to user confidence and token value.
Mitigation strategies for CVE-2018-13604 require immediate code review and implementation of proper integer bounds checking mechanisms. Developers should implement comprehensive input validation and use safe arithmetic operations that explicitly check for overflow conditions before performing balance updates. The recommended approach includes utilizing libraries such as OpenZeppelin's SafeMath or similar arithmetic libraries that provide overflow protection for all mathematical operations. Additionally, contract owners should conduct thorough security audits and employ formal verification techniques to identify similar vulnerabilities in other functions. The solution must also include proper access control mechanisms and transparent logging of all mintToken operations to detect unauthorized activities. Organizations should consider implementing multi-signature wallets for contract ownership and establish regular security review processes to prevent similar vulnerabilities from being introduced in future smart contract deployments. This vulnerability also highlights the importance of adhering to established security frameworks and best practices outlined in the ATT&CK framework for blockchain security, particularly those related to smart contract exploitation and privilege escalation techniques.