CVE-2018-13222 in ObjectToken
Summary
by MITRE
The sell function of a smart contract implementation for ObjectToken (OBJ), an Ethereum token, has an integer overflow in which "amount * sellPrice" can be zero, consequently reducing a seller's assets.
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Analysis
by VulDB Data Team • 02/25/2020
The vulnerability identified in CVE-2018-13222 represents a critical integer overflow flaw within the sell function of the ObjectToken (OBJ) smart contract deployed on the Ethereum blockchain. This issue stems from inadequate input validation and arithmetic operation handling within the contract's code, creating a scenario where mathematical calculations can produce unexpected results due to overflow conditions. The vulnerability specifically affects the calculation involving "amount * sellPrice" which serves as a fundamental component in determining the value of tokens being sold by users. When this multiplication operation exceeds the maximum value that can be represented by the data type used, the result wraps around to zero or another incorrect value, fundamentally compromising the contract's financial integrity. Such integer overflow conditions fall under the CWE-190 category of integer overflow/underflow, which represents one of the most common and dangerous classes of vulnerabilities in smart contract implementations. The flaw creates a direct financial incentive for malicious actors to exploit this condition, as it allows them to manipulate the token selling process and potentially drain assets from sellers.
The operational impact of this vulnerability extends beyond simple financial loss, as it fundamentally undermines the trust and reliability of the smart contract system. When the sell function produces incorrect calculations due to integer overflow, sellers may receive significantly less value than they are entitled to for their tokens, or in extreme cases, the transaction may appear to succeed while actually transferring no value. This creates a scenario where legitimate users lose assets while the attacker can manipulate the system to their advantage. The vulnerability demonstrates poor defensive programming practices in smart contract development, where developers failed to implement proper bounds checking and overflow protection mechanisms. The attack vector is particularly concerning because it can be executed by any user who attempts to sell tokens, making it a persistent threat that affects all participants in the token ecosystem. From an attacker's perspective, this vulnerability aligns with techniques described in the ATT&CK framework under the T1059.001 sub-technique for command and control through smart contract manipulation, as it allows for unauthorized value extraction through legitimate transaction paths.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security architecture improvements. The primary fix involves implementing comprehensive input validation and arithmetic overflow protection throughout the contract's codebase, specifically ensuring that multiplication operations check for potential overflow conditions before execution. Developers should utilize established libraries and patterns such as OpenZeppelin's SafeMath library to prevent integer overflows, which provides safe arithmetic operations that automatically check for overflow conditions and revert transactions when they occur. The contract should also implement proper bounds checking on all user inputs, particularly the amount and sellPrice parameters, to ensure they fall within acceptable ranges before any calculations are performed. Additionally, comprehensive testing including fuzz testing and formal verification should be conducted to identify similar vulnerabilities across the entire smart contract codebase. Organizations implementing similar token contracts should adopt security-by-design principles and follow established best practices for smart contract development, including regular security audits and code reviews. The vulnerability highlights the critical importance of adhering to security standards such as those defined in the OWASP Smart Contract Security Verification Standard, which specifically addresses integer overflow conditions and recommends defensive programming techniques to prevent such issues in blockchain applications.