CVE-2018-13628 in MomentumToken
Summary
by MITRE
The mintToken function of a smart contract implementation for MomentumToken, 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-2018-13628 represents a critical integer overflow flaw within the mintToken function of the MomentumToken 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 malicious actors can manipulate token balances through controlled overflow conditions. The flaw specifically affects the contract's ability to handle large numerical values during token minting operations, allowing for unauthorized balance manipulation that directly impacts the integrity of the token economy.
The technical execution of this vulnerability occurs when the mintToken function processes user inputs without proper bounds checking or overflow detection mechanisms. When an attacker provides carefully crafted parameters that exceed the maximum value that can be represented by the underlying integer type, the system wraps around to a much smaller value due to the overflow behavior. This creates a scenario where the owner can manipulate the balance of any user account to an arbitrary value, effectively allowing for unlimited token creation or balance manipulation. The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions in software implementations, and demonstrates how these classical programming flaws translate into blockchain-specific security risks.
The operational impact of this vulnerability extends far beyond simple balance manipulation, as it fundamentally compromises the trustless nature of the token system and creates potential for significant financial loss. An attacker with access to the contract owner privileges can systematically manipulate user balances to create artificial wealth or drain funds from other accounts, potentially leading to market manipulation and loss of confidence in the token. The vulnerability also enables potential denial of service scenarios where an attacker could set balances to zero for critical accounts or set extremely high values that could cause downstream contract failures. This type of vulnerability directly violates the core principles of blockchain security and can result in complete loss of funds for users who hold the affected tokens.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and integer overflow protection mechanisms within the smart contract code. The recommended approach involves adding explicit bounds checking before any arithmetic operations, implementing safe math libraries that automatically detect and prevent overflow conditions, and ensuring that all integer operations within the mintToken function include proper validation. Organizations should also consider implementing multi-signature ownership controls and regular security audits to prevent unauthorized access to privileged functions. From an ATT&CK framework perspective, this vulnerability represents a privilege escalation technique that allows attackers to manipulate account balances, and defensive measures should include monitoring for unusual balance changes and implementing proper access controls. Additionally, the contract should be redesigned to use more robust data types and validation mechanisms that prevent such arithmetic overflows from occurring in the first place, ensuring that the token system maintains its integrity and user trust.