CVE-2018-13660 in BillionRewardsToken
Summary
by MITRE
The mint function of a smart contract implementation for BillionRewardsToken, 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-2018-13660 resides within the BillionRewardsToken smart contract implementation on the Ethereum blockchain, representing a critical integer overflow flaw that fundamentally compromises the contract's integrity and security model. This vulnerability specifically affects the mint function, which is designed to create new tokens and distribute them to users within the token ecosystem. The integer overflow occurs when the mint function processes token creation requests without proper bounds checking, allowing an attacker with owner privileges to manipulate the token supply mechanism in ways that were never intended by the contract's original design.
The technical exploitation of this vulnerability stems from the absence of overflow protection mechanisms within the mint function's implementation. When the contract attempts to increment token balances or total supply values beyond the maximum limit of the underlying data type, the integer overflow causes the value to wrap around to zero or a negative number, creating unpredictable behavior. This flaw directly maps to CWE-190, which describes integer overflow and underflow conditions, and represents a classic example of insufficient input validation in smart contract development. The vulnerability is particularly dangerous because it grants the contract owner unprecedented control over user balances, effectively allowing them to manipulate the token distribution mechanism to arbitrary values.
The operational impact of this vulnerability extends far beyond simple balance manipulation, creating a comprehensive security risk that undermines the fundamental trust model of the token ecosystem. An attacker with owner access can increase any user's balance to any desired amount, potentially leading to massive inflation of the token supply and complete devaluation of the currency. This capability also enables sophisticated attacks such as creating artificial demand by inflating specific user accounts, manipulating token price mechanisms, or even enabling theft of funds from other users by setting their balances to zero while simultaneously inflating the attacker's own holdings. The vulnerability creates a pathway for financial loss and market manipulation that can destabilize the entire token economy.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements in smart contract development practices. The primary fix involves implementing proper overflow protection mechanisms using modern Solidity versions that include built-in overflow checks or explicit validation routines before any arithmetic operations in the mint function. Organizations should adopt defensive programming practices such as using safe math libraries that automatically detect and prevent overflow conditions, as recommended by the OpenZeppelin security guidelines. Additionally, the contract should implement comprehensive access control measures and regular security audits to prevent unauthorized access to privileged functions. This vulnerability highlights the importance of adhering to established security frameworks and best practices in blockchain development, including the principles outlined in the OWASP Smart Contract Security Verification Standard and the ATT&CK framework for blockchain-based attacks, which emphasizes the need for robust input validation and privilege separation in decentralized applications.