CVE-2018-13632 in NEXPARA
Summary
by MITRE
The mintToken function of a smart contract implementation for NEXPARA, 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-2018-13632 represents a critical integer overflow flaw within the mintToken function of the NEXPARA Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic handling within the smart contract code, creating a scenario where the contract owner can manipulate user balances arbitrarily. The flaw manifests when the mintToken function processes token minting operations without adequate overflow checks, allowing malicious or authorized contract owners to execute calculations that exceed the maximum value representable by the integer data type, thereby enabling unauthorized balance manipulation. Such vulnerabilities are particularly dangerous in decentralized finance applications where token balances directly control user assets and transactional integrity.
The technical exploitation of this vulnerability occurs through the manipulation of the mintToken function parameters, specifically targeting the integer arithmetic operations that govern token creation and distribution. When the contract processes mint operations, the integer overflow allows the owner to bypass normal balance limits and set arbitrary user balances, potentially enabling the creation of unlimited tokens or manipulation of existing balances. This type of vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a classic example of how insufficient input validation can lead to severe financial consequences in blockchain environments. The underlying issue demonstrates poor software engineering practices in smart contract development where proper boundary checking and arithmetic validation are omitted, creating exploitable pathways for unauthorized balance manipulation.
The operational impact of CVE-2018-13632 extends beyond simple balance manipulation to encompass potential financial loss, contract integrity compromise, and broader ecosystem trust degradation. An attacker with access to the contract owner privileges can manipulate user accounts to create artificial wealth, potentially enabling fraudulent transactions, market manipulation, or even complete contract takeovers. This vulnerability directly impacts the fundamental principles of blockchain security, particularly the immutability and trustless nature of smart contracts, as it allows for arbitrary state changes that violate the expected behavior of the token system. The consequences ripple through the entire token ecosystem, affecting user confidence, exchange listings, and the overall stability of the NEXPARA token within the Ethereum blockchain environment.
Mitigation strategies for this vulnerability require immediate contract upgrades and comprehensive security auditing of existing smart contract implementations. The primary remediation involves implementing proper integer overflow protection through explicit boundary checks, using safe arithmetic libraries, or employing modern programming practices that prevent such conditions from occurring. Organizations should implement formal verification techniques and adhere to established security standards such as those outlined in the Ethereum Smart Contract Security Best Practices, which recommend using libraries like OpenZeppelin's SafeMath for arithmetic operations. Additionally, regular security audits, code reviews, and penetration testing should be conducted to identify similar vulnerabilities across the entire smart contract ecosystem. The vulnerability also highlights the importance of proper access control mechanisms and the principle of least privilege in smart contract design, ensuring that contract owners cannot arbitrarily manipulate user balances without proper authorization and transparent auditing mechanisms.