CVE-2018-13647 in TrueGoldCoinToken
Summary
by MITRE
The mintToken function of a smart contract implementation for TrueGoldCoinToken, 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-2018-13647 represents a critical integer overflow flaw within the mintToken function of the TrueGoldCoinToken smart contract implementation on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic handling within the contract's code, specifically affecting the token's issuance mechanism. The flaw allows the contract owner to manipulate user balances through a mathematical overflow condition, creating a fundamental security breach in the token's access control and distribution system.
The technical execution of this vulnerability occurs when the mintToken function processes token minting operations without proper bounds checking on the amount parameter. In Ethereum smart contracts, integer overflows occur when arithmetic operations exceed the maximum value that can be stored in a given data type, causing the value to wrap around to zero or a negative number. This specific implementation fails to validate the input parameters before performing arithmetic operations, enabling the contract owner to craft malicious inputs that exploit the overflow behavior. The vulnerability maps directly to CWE-190, which defines integer overflow conditions, and specifically aligns with CWE-682, which addresses incorrect arithmetic operations in software systems.
The operational impact of this vulnerability extends far beyond simple balance manipulation, as it fundamentally compromises the integrity of the token economy. An attacker with owner privileges can arbitrarily set any user's token balance to any desired value, potentially creating unlimited tokens or zeroing out user holdings. This capability enables various malicious activities including unauthorized token distribution, wealth redistribution, or even complete token value manipulation that could destabilize the entire token ecosystem. The vulnerability essentially provides the contract owner with a backdoor to control token distribution without legitimate authorization from token holders, undermining the decentralized trust model that blockchain systems are designed to maintain.
From a threat modeling perspective, this vulnerability aligns with several ATT&CK techniques including T1059.001 for command and control through smart contract manipulation, T1548.001 for privilege escalation, and T1496 for resource hijacking. The vulnerability also represents a significant risk to the broader Ethereum ecosystem, as it demonstrates how seemingly minor coding flaws in smart contract implementations can create substantial financial risks. The impact is particularly severe because it affects the core token functionality and can be exploited without requiring external network access or complex attack vectors, making it highly accessible to malicious actors who gain access to the owner account.
Mitigation strategies for this vulnerability require immediate code remediation through comprehensive input validation and overflow protection mechanisms. The smart contract implementation must include explicit bounds checking before any arithmetic operations, utilize safe math libraries such as OpenZeppelin's SafeMath, and implement proper access controls to prevent unauthorized modifications to token balances. Additionally, the contract should undergo thorough security auditing by third-party experts and implement continuous monitoring systems to detect anomalous balance changes. Regular code reviews and formal verification processes should become standard practice for all smart contract deployments to prevent similar vulnerabilities from emerging in future implementations. The vulnerability also underscores the importance of proper security testing methodologies including fuzzing, symbolic execution, and manual code review processes that can identify these critical arithmetic flaws before deployment to production networks.