CVE-2018-13678 in Lottery
Summary
by MITRE
The mintToken function of a smart contract implementation for Lottery, 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.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/28/2020
The vulnerability identified in CVE-2018-13678 resides within the mintToken function of an Ethereum smart contract implementation for a Lottery token, representing a critical integer overflow flaw that fundamentally compromises the contract's integrity and user asset security. This vulnerability specifically affects the token's ability to manage user balances through the mintToken function, where the contract fails to properly validate or constrain numeric inputs during balance modifications. The integer overflow occurs when the contract attempts to increment user balances without adequate boundary checks, allowing an attacker with owner privileges to manipulate the balance of any user account to arbitrary values. This flaw directly violates the fundamental principles of secure smart contract development and represents a clear violation of the CWE-190 weakness category, which encompasses integer overflow conditions that can lead to unpredictable behavior and unauthorized access. The vulnerability enables a malicious actor with owner access to manipulate the token distribution and potentially drain or manipulate user holdings in ways that could severely impact the token's economic model and user trust.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial loss, contract integrity compromise, and systemic risk to the entire token ecosystem. When an attacker exploits this integer overflow, they can effectively create unlimited tokens or manipulate existing balances to achieve unauthorized access to funds. The vulnerability allows for the creation of negative balances or extremely large balances that exceed the token's intended supply limits, potentially enabling attacks such as balance manipulation to drain funds from other users or artificially inflate the attacker's own holdings. This type of vulnerability falls under the ATT&CK technique T1059.006 for smart contract exploitation and represents a sophisticated attack vector that leverages the mathematical properties of integer arithmetic to bypass normal contract security controls. The vulnerability's impact is particularly severe because it operates at the core level of token management, where user balances are maintained and validated, creating a fundamental weakness that can be exploited to undermine the entire token economy.
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 proper input validation and boundary checking within the mintToken function to prevent integer overflows during balance updates, which aligns with security best practices outlined in the CWE-190 category. Smart contract developers should implement explicit checks using require statements or similar validation mechanisms to ensure that balance updates remain within reasonable limits and that no overflow conditions can occur. Additionally, comprehensive testing including fuzz testing and formal verification should be employed to identify similar vulnerabilities in contract logic. The implementation should also consider using established libraries and frameworks that provide built-in overflow protection mechanisms, such as OpenZeppelin's SafeMath library, which helps prevent integer overflows through explicit mathematical operation checks. Regular security audits and code reviews should be conducted to identify potential integer overflow vulnerabilities and other security weaknesses that could compromise the contract's integrity and user funds.