CVE-2018-13733 in ProjectJ
Summary
by MITRE
The mintToken function of a smart contract implementation for ProjectJ, 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 in CVE-2018-13733 represents a critical integer overflow flaw within the mintToken function of ProjectJ's Ethereum token smart contract implementation. This vulnerability falls under the CWE-190 category of integer overflow and under the ATT&CK technique T1210 for exploitation of remote services. The flaw occurs when the mintToken function processes token minting operations without proper bounds checking on the balance values, creating a scenario where arithmetic operations can exceed the maximum value that can be represented by the underlying data type. The integer overflow vulnerability specifically affects the balance calculations within the token contract, allowing an attacker to manipulate the token supply and user balances through carefully crafted inputs that cause the arithmetic operations to wrap around to unexpected values.
The operational impact of this vulnerability is severe and multifaceted, as it grants the contract owner unprecedented control over the token ecosystem. An attacker with owner privileges can manipulate user balances to arbitrary values, potentially allowing them to create unlimited tokens or manipulate specific user accounts to have excessive balances. This creates a fundamental breach of trust within the token system and can lead to significant financial losses for users who hold tokens in the affected contract. The vulnerability essentially allows for a form of theft by inflation, where the attacker can effectively create new tokens without proper authorization, or by manipulation, where they can alter existing balances to their advantage. The implications extend beyond simple financial gain as this vulnerability can undermine the entire economic model of the token and potentially compromise the integrity of the entire blockchain-based system relying on this contract.
The technical exploitation of this vulnerability requires the attacker to have owner access to the contract, which represents a privilege escalation issue within the access control model of the smart contract. The vulnerability demonstrates poor input validation and inadequate boundary checking within the mintToken function, which should have implemented proper overflow protection mechanisms such as require statements or SafeMath libraries commonly used in Ethereum smart contracts. The flaw represents a failure in the secure coding practices for blockchain applications, as the contract should have validated that the resulting balance would not exceed the maximum value representable by the data type. Organizations and developers should implement comprehensive testing procedures including formal verification and static analysis tools to identify similar vulnerabilities in smart contract implementations. The mitigation strategy involves patching the vulnerable function to include proper overflow checks and implementing robust access control mechanisms, while also ensuring that all arithmetic operations within smart contracts utilize secure mathematical libraries to prevent similar issues from occurring in future implementations.