CVE-2018-13685 in Vornox
Summary
by MITRE
The mintToken function of a smart contract implementation for Vornox (VRX) (Contract Name: VornoxCoinToken), 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-2018-13685 represents a critical integer overflow flaw within the mintToken function of the Vornox (VRX) smart contract implementation on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic operation handling within the contract's codebase, specifically affecting the token distribution mechanism. The flaw allows the contract owner to manipulate user balances arbitrarily, creating a fundamental breach in the token's integrity and trust model. The vulnerability manifests when the mintToken function processes token minting operations without proper overflow checks, enabling malicious or accidental manipulation of account balances through crafted input parameters.
The technical implementation of this vulnerability directly relates to CWE-190, which describes integer overflow conditions where an operation on a signed or unsigned integer results in a value that exceeds the maximum representable value for that integer type. In the context of Ethereum smart contracts, this typically occurs when arithmetic operations are performed without proper boundary checks, particularly in functions that modify account balances or token quantities. The mintToken function likely performs operations such as balance += amount or similar arithmetic assignments without validating that the resulting values remain within acceptable integer ranges. This allows an attacker with owner privileges to craft specific inputs that cause the arithmetic to wrap around to unexpected values, potentially enabling the creation of unlimited tokens or manipulation of arbitrary user balances.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass fundamental security breaches within the token ecosystem. An attacker with owner access can arbitrarily inflate user balances, potentially creating an artificial supply of tokens that could disrupt market dynamics and undermine the economic model of the Vornox token. The vulnerability also poses significant risks to user funds and trust in the platform, as it enables the possibility of unauthorized token creation and distribution. Additionally, this flaw can compromise the overall integrity of the blockchain ledger by allowing manipulation of token supply records and account balances, potentially leading to cascading effects in smart contract systems that depend on accurate token state information. The vulnerability also impacts the contract's compliance with standard token implementations and could lead to issues with exchanges and other systems that rely on predictable token behavior.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements in smart contract development practices. The primary solution involves implementing proper integer overflow protection mechanisms, including the use of safe math libraries such as OpenZeppelin's SafeMath implementation, which provides checked arithmetic operations that revert transactions when overflow or underflow conditions occur. Contract developers should also implement comprehensive input validation for all functions that modify token balances, ensuring that all arithmetic operations include appropriate boundary checks and that the mintToken function validates all input parameters before processing. Additionally, the contract should implement proper access control mechanisms to limit who can invoke the mintToken function, and consider implementing audit trails or logging mechanisms to track balance modifications. The vulnerability also highlights the importance of thorough code review processes and formal verification techniques, as outlined in the ATT&CK framework's software development practices, to identify and prevent similar flaws in future implementations. Regular security audits and adherence to established smart contract security standards are essential to prevent recurrence of such vulnerabilities in the Ethereum ecosystem.