CVE-2018-13471 in BeyondCashToken
Summary
by MITRE
The mintToken function of a smart contract implementation for BeyondCashToken, 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 • 02/26/2020
The vulnerability identified as CVE-2018-13471 represents a critical integer overflow flaw within the mintToken function of the BeyondCashToken smart contract implementation 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, creating a scenario where the owner can manipulate token balances beyond normal constraints. The flaw specifically manifests when the mintToken function processes token creation requests without adequate overflow checks, allowing malicious actors with ownership privileges to exploit the contract's arithmetic operations.
The technical implementation of this vulnerability aligns with CWE-190, which describes integer overflow conditions that occur when an integer value is incremented beyond its maximum representable value, causing it to wrap around to the minimum value. In the context of Ethereum smart contracts, this issue typically arises from the use of Solidity's uint256 data types without proper bounds checking mechanisms. The vulnerability enables an attacker to perform arithmetic operations that result in unexpected behavior, particularly when dealing with balance updates and token minting processes. The contract's mintToken function likely performs operations such as balance += amount without verifying that the resulting value remains within valid integer boundaries.
The operational impact of this vulnerability extends beyond simple balance manipulation, as it fundamentally compromises the integrity of the token economy and can lead to severe financial consequences for users and the project. An attacker with ownership access can arbitrarily set any user's token balance to any desired value, potentially creating unlimited tokens or manipulating balances to gain unfair advantages. This vulnerability undermines the core principles of blockchain security and trust, as it allows for the creation of an uncontrolled supply of tokens that can be used for fraudulent activities, market manipulation, or unauthorized transfers. The implications are particularly severe in DeFi ecosystems where token balances directly affect liquidity pools, governance rights, and financial obligations.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security practices within smart contract development. The primary solution involves implementing comprehensive input validation and overflow protection mechanisms, such as using require statements to validate arithmetic operations and employing libraries like OpenZeppelin's SafeMath for all mathematical operations. The contract should enforce bounds checking on all balance updates and token minting processes to prevent integer overflow conditions. Additionally, regular security audits and formal verification processes should be implemented to identify similar vulnerabilities across the entire codebase. Organizations should also consider implementing multi-signature ownership controls and time locks for critical contract functions to reduce the attack surface. This vulnerability demonstrates the critical importance of adhering to secure coding practices in blockchain development and aligns with ATT&CK technique T1548.001 for privilege escalation through contract manipulation, emphasizing the need for robust access controls and comprehensive security testing in smart contract implementations.