CVE-2018-13500 in MSXAdvanced
Summary
by MITRE
The mintToken function of a smart contract implementation for MSXAdvanced, 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.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/27/2020
The vulnerability identified in CVE-2018-13500 represents a critical integer overflow flaw within the mintToken function of the MSXAdvanced Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic operations that fail to account for boundary conditions in the token minting process. The flaw allows the contract owner to manipulate user balances arbitrarily, fundamentally compromising the integrity of the token ecosystem. The vulnerability is classified under CWE-190 as an integer overflow condition, specifically manifesting as an unsigned integer overflow that occurs when the mintToken function processes token minting operations without adequate overflow checking mechanisms.
The technical execution of this vulnerability relies on the contract owner exploiting the lack of proper bounds checking in the mintToken function implementation. When the owner invokes this function with carefully crafted parameters, the integer overflow enables them to manipulate the balance of any user account within the token system. The flaw occurs because the smart contract does not validate that the addition of new tokens to a user's balance would exceed the maximum value that can be represented by the underlying data type. This creates a scenario where arithmetic operations can wrap around to zero or negative values, allowing the attacker to set arbitrary balances for target accounts. The vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059.006 for smart contract manipulation and T1068 for privilege escalation within blockchain environments.
The operational impact of this vulnerability extends far beyond simple balance manipulation, creating cascading effects throughout the token economy and potentially enabling more sophisticated attacks. An attacker with owner privileges can inflate user balances to extreme values, potentially disrupting the token's economic model and enabling unauthorized transfers or exchanges. The vulnerability also affects the token's total supply calculation, as the integer overflow can result in incorrect accounting of minted tokens. This manipulation capability undermines the fundamental trust assumptions in decentralized applications and can lead to loss of funds for other users who rely on the token's integrity. The vulnerability's severity is amplified by the fact that it requires minimal privileges to exploit, as the contract owner typically has elevated access rights that are not properly constrained by the overflow protection mechanisms.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements to prevent similar issues in future smart contract implementations. The primary fix involves implementing comprehensive input validation and overflow checking mechanisms within the mintToken function, ensuring that all arithmetic operations include proper boundary checks before updating user balances. Developers should utilize established safe math libraries and formal verification techniques to prevent integer overflows in smart contracts, as recommended by the Solidity documentation and security best practices. Additionally, contract owners should implement proper access controls and audit mechanisms to monitor token minting operations, while also considering the use of multi-signature wallets and time locks for critical operations. The vulnerability highlights the importance of adhering to security standards such as the OpenZeppelin security guidelines and implementing comprehensive testing including fuzzing and formal verification to identify potential integer overflow scenarios before deployment.