CVE-2018-13188 in MyBO
Summary
by MITRE
The mintToken function of a smart contract implementation for MyBO, 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 • 02/25/2020
The vulnerability identified as CVE-2018-13188 resides within the mintToken function of MyBO smart contract implementation on the Ethereum blockchain. This critical flaw represents an integer overflow condition that fundamentally compromises the contract's tokenomics and security model. The vulnerability allows the contract owner to manipulate user balances arbitrarily, effectively enabling them to create unlimited tokens or modify existing token holdings without proper authorization. The integer overflow occurs when the mintToken function fails to properly validate or constrain input values during token creation processes, leading to unexpected behavior in the underlying arithmetic operations.
The technical nature of this vulnerability aligns with CWE-190, which describes integer overflow and underflow conditions in software implementations. In Ethereum smart contracts, such vulnerabilities manifest when mathematical operations exceed the maximum value that can be represented by the data type being used. The mintToken function likely performs arithmetic operations on token balances without proper bounds checking, allowing an attacker with owner privileges to input malicious values that wrap around the integer limits. This creates a scenario where normal 256-bit unsigned integer arithmetic produces unexpected results, enabling the contract owner to set arbitrary user balances to values that may exceed the intended token supply limits or manipulate other users' holdings.
From an operational perspective, this vulnerability creates significant risks for token holders and the overall ecosystem. The contract owner can effectively create unlimited tokens or manipulate existing balances, potentially leading to severe economic disruption and loss of trust in the token. The impact extends beyond simple financial loss as it undermines the fundamental principles of blockchain transparency and immutability. Users may lose confidence in the token's value proposition, and the vulnerability creates opportunities for financial manipulation that could be exploited for profit or to destabilize the token's market position. The vulnerability also creates potential for denial of service attacks where malicious owners could manipulate balances to prevent legitimate transactions or access to funds.
Mitigation strategies for this vulnerability involve implementing proper input validation and boundary checking within the mintToken function. Smart contract developers should utilize safe math libraries that include overflow checks, such as OpenZeppelin's SafeMath implementation, which prevents arithmetic operations from causing overflow conditions. The contract should validate all input parameters before performing any arithmetic operations and implement proper access control measures to ensure that only authorized parties can execute mint operations. Additionally, regular security audits and formal verification processes should be conducted to identify and remediate similar vulnerabilities in smart contract implementations. The vulnerability highlights the importance of following secure coding practices in blockchain development and the necessity of comprehensive testing including edge case scenarios that could trigger integer overflow conditions. Organizations should also consider implementing multi-signature ownership controls and time locks for critical operations to reduce the risk associated with single points of failure in contract ownership.