CVE-2018-13707 in YSS
Summary
by MITRE
The mintToken function of a smart contract implementation for YSS, 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-2018-13707 represents a critical integer overflow flaw within the mintToken function of the YSS Ethereum token smart contract implementation. This vulnerability resides in the core token functionality that allows for the creation and distribution of new tokens, making it particularly dangerous as it directly impacts the token economy and user asset integrity. The flaw enables the contract owner to manipulate token balances in ways that could lead to significant financial losses and system instability. The vulnerability is classified under CWE-190 as an integer overflow, specifically manifesting as an unchecked arithmetic operation that can produce unexpected results when dealing with maximum integer values.
The technical execution of this vulnerability occurs through the mintToken function where insufficient input validation and overflow checking mechanisms allow an attacker with owner privileges to manipulate the token supply and user balances. When the mintToken function processes token creation requests, it fails to properly validate the input parameters, particularly the amount parameter that determines how many tokens to mint. This oversight creates an opportunity where an attacker can craft malicious inputs that cause integer overflow conditions, effectively bypassing normal token accounting mechanisms. The vulnerability is particularly concerning because it allows for arbitrary balance manipulation, meaning the contract owner can set any user's balance to any desired value, potentially creating infinite token balances or zeroing out user holdings.
The operational impact of this vulnerability extends beyond simple financial manipulation to encompass broader security and trust implications within the Ethereum ecosystem. An attacker exploiting this vulnerability could potentially drain user funds, create artificial token scarcity, or manipulate token distribution to gain unfair advantages. The vulnerability affects the fundamental trust model of the token system, as users cannot rely on the integrity of their token balances. From a security perspective, this vulnerability represents a privilege escalation issue where the owner's elevated permissions are misused to compromise the entire token economy. The attack vector is particularly dangerous because it requires no external dependencies beyond having owner access, making it an internal threat that can be exploited without complex external conditions.
Mitigation strategies for this vulnerability must address both the immediate technical flaw and broader security practices within smart contract development. The primary fix involves implementing proper integer overflow checks and input validation within the mintToken function, utilizing safe arithmetic operations that prevent overflow conditions. Security best practices recommend employing established libraries and frameworks that handle integer arithmetic safely, such as OpenZeppelin's SafeMath library, which provides overflow-checked arithmetic operations. Additionally, implementing comprehensive access control mechanisms and regular security audits can help prevent unauthorized exploitation. The vulnerability highlights the importance of adhering to security standards like those defined in the OWASP Smart Contract Security Verification Standard and aligns with ATT&CK techniques related to privilege escalation and resource manipulation within blockchain environments. Organizations should also consider implementing multi-signature wallet solutions and regular code reviews to minimize the risk of similar vulnerabilities in future deployments.