CVE-2018-13747 in VanMinhCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for VanMinhCoin, 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 identified as CVE-2018-13747 represents a critical integer overflow flaw within the mintToken function of the VanMinhCoin Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic operation handling within the smart contract code, specifically affecting the token's issuance mechanism. The integer overflow occurs when the contract attempts to increment token balances without adequate bounds checking, creating a scenario where mathematical operations can exceed the maximum value that can be represented by the data type used. Such flaws are particularly dangerous in blockchain environments where financial assets are at stake and where transactions are irreversible once confirmed on the blockchain. The vulnerability is classified under CWE-190 as an integer overflow or wraparound, which represents a well-known category of software defects that can lead to unpredictable behavior and security breaches in cryptographic systems.
The operational impact of this vulnerability is severe and directly exploitable by the contract owner, who can manipulate token balances of arbitrary users within the system. This creates a fundamental breach of trust and financial integrity within the token ecosystem, as the malicious actor can effectively create unlimited tokens or manipulate existing balances to their advantage. The vulnerability allows for arbitrary balance manipulation because the mintToken function does not properly validate or constrain the input parameters that determine how many tokens to mint and to which user account they should be credited. This flaw essentially provides the contract owner with a backdoor mechanism to arbitrarily control token distribution and potentially drain the system of its assets. The exploitability of this vulnerability is high since it requires no external conditions beyond the existing owner privileges, making it particularly dangerous in permissioned environments where the owner may have malicious intent or where owner privileges have been compromised.
The security implications extend beyond simple balance manipulation to encompass potential financial loss, system compromise, and loss of user confidence in the token ecosystem. Smart contracts operate under the assumption that all transactions and state changes are valid and secure, but this vulnerability undermines that fundamental principle by allowing the contract owner to bypass normal token issuance and distribution rules. The vulnerability aligns with ATT&CK technique T1548.001 which covers privilege escalation through code injection and manipulation of system processes. In the context of Ethereum smart contracts, this vulnerability represents a failure in the principle of least privilege and proper access control mechanisms. The integer overflow specifically affects the contract's ability to maintain accurate accounting of token balances, potentially leading to double-spending scenarios, unauthorized minting, and overall system instability. This flaw also demonstrates poor software development practices in the context of blockchain development, where security considerations must be paramount due to the immutable nature of blockchain transactions and the irreversible consequences of such vulnerabilities. Organizations and developers should implement comprehensive testing including formal verification methods and security audits to prevent such vulnerabilities from being deployed in production environments where they could cause significant financial harm to users and stakeholders.