CVE-2018-13569 in HitToken
Summary
by MITRE
The mintToken function of a smart contract implementation for HitToken, 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 • 02/27/2020
The vulnerability identified as CVE-2018-13569 represents a critical integer overflow flaw within the mintToken function of HitToken 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. The flaw allows the contract owner to manipulate token balances of arbitrary users by exploiting the overflow behavior, effectively enabling unauthorized balance manipulation that can compromise the integrity of the entire token ecosystem.
The technical implementation of this vulnerability occurs within the mintToken function where the smart contract performs arithmetic operations without proper bounds checking or overflow detection mechanisms. When the contract attempts to increment token balances or perform calculations involving large integer values, the system fails to validate whether these operations exceed the maximum representable values for the underlying data types. This creates a scenario where mathematical overflow occurs, allowing an attacker with owner privileges to craft specific inputs that result in unexpected balance values. The vulnerability is classified under CWE-190, which specifically addresses integer overflow and underflow conditions in software implementations.
The operational impact of this vulnerability extends far beyond simple balance manipulation, as it fundamentally compromises the security and trust model of the HitToken ecosystem. An attacker with owner access can arbitrarily set any user's token balance to zero, to maximum values, or to any other desired amount, effectively enabling theft of tokens from other users or creation of unlimited supply. This type of vulnerability directly violates the core principles of blockchain security and can lead to significant financial losses for token holders. The attack vector aligns with ATT&CK technique T1059.006, which involves the use of smart contract vulnerabilities to manipulate system behavior, and T1496, which targets data manipulation through software exploitation.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and arithmetic boundary checks within the smart contract code. Developers must implement explicit overflow detection mechanisms using modern Solidity practices such as require statements with appropriate conditions, or utilize SafeMath libraries that provide checked arithmetic operations. The contract owner should also implement proper access controls and audit procedures to prevent unauthorized access to privileged functions. Additionally, regular security audits and formal verification of smart contract code should become standard practice to identify and remediate similar vulnerabilities before they can be exploited in production environments. The vulnerability demonstrates the critical importance of adhering to secure coding practices in blockchain development and the necessity of thorough testing for edge cases involving integer arithmetic operations.