CVE-2018-13160 in etktokens
Summary
by MITRE
The mintToken function of a smart contract implementation for etktokens (ETK), 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 • 02/25/2020
The vulnerability described in CVE-2018-13160 represents a critical integer overflow flaw within the mintToken function of the etktokens (ETK) smart contract deployed 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. The flaw allows the contract owner to manipulate token balances by setting them to arbitrary values, effectively bypassing normal token issuance and transfer mechanisms. The vulnerability directly impacts the fundamental integrity of the token economy by enabling unauthorized balance manipulation that could lead to inflationary attacks or malicious redistribution of tokens.
The technical implementation of this vulnerability occurs within the mintToken function where integer overflow conditions are not properly handled. When the contract attempts to increment token balances or perform arithmetic operations on token amounts, the system fails to validate that the resulting values remain within the acceptable range of the integer data types used. This creates a scenario where an attacker with owner privileges can force the system to wrap around integer values, allowing them to set user balances to extremely large or negative values. The vulnerability is classified under CWE-190 as an integer overflow condition, specifically involving signed integer overflow that can result in unexpected behavior when arithmetic operations exceed the maximum representable value.
From an operational perspective, this vulnerability presents significant risks to both the token ecosystem and its users. The contract owner can manipulate balances to create unlimited tokens or set balances to malicious values that could disrupt normal trading operations or cause the contract to behave unpredictably. The impact extends beyond simple financial loss as it undermines trust in the smart contract system and could potentially allow for more sophisticated attacks such as reentrancy exploits or other manipulation techniques that leverage the compromised balance states. The vulnerability affects all users of the ETK token who may have their balances manipulated without their knowledge or consent, creating a fundamental breach of the token's intended functionality.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protections within the smart contract code. The recommended approach involves adding explicit bounds checking and validation before any arithmetic operations are performed, ensuring that all input values are validated against maximum and minimum thresholds. Additionally, developers should implement overflow protection mechanisms such as using libraries like OpenZeppelin's SafeMath or similar secure arithmetic operations that automatically detect and prevent overflow conditions. The contract owner should also implement proper access controls and audit logging to monitor any balance modifications and establish a more robust governance model that prevents single points of failure. Organizations should conduct comprehensive security audits of all smart contracts and implement continuous monitoring systems to detect similar vulnerabilities in their blockchain applications. This vulnerability demonstrates the critical importance of following secure coding practices in blockchain environments and adheres to ATT&CK technique T1499.004 related to resource hijacking through manipulation of token balances and smart contract functionality.