CVE-2018-13740 in OneChain
Summary
by MITRE
The mintToken function of a smart contract implementation for OneChain, 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 • 03/03/2020
The vulnerability identified as CVE-2018-13740 resides within the mintToken function of a smart contract implementation for OneChain, an Ethereum-based token system. This flaw represents a critical integer overflow condition that fundamentally compromises the contract's integrity and financial security mechanisms. The vulnerability allows the contract owner to manipulate user balances arbitrarily, creating a severe risk for token holders and the overall ecosystem. The issue stems from improper input validation and arithmetic handling within the mintToken function, which fails to properly check for overflow conditions when processing token minting operations. This type of vulnerability directly violates the fundamental principles of secure smart contract development and demonstrates a critical failure in the contract's mathematical operations.
The technical implementation of this vulnerability manifests through the absence of proper overflow checks in the mintToken function's arithmetic operations. When the contract owner invokes this function, the system fails to validate whether the resulting balance would exceed the maximum value that can be represented by the data type used for balance storage. This oversight creates a scenario where an attacker with owner privileges can manipulate the token supply and user balances beyond normal operational parameters. The vulnerability specifically aligns with CWE-190, which identifies integer overflow and underflow conditions as critical security flaws in software systems. The lack of boundary checking in the token minting process allows for the creation of arbitrarily large balances, effectively enabling the contract owner to manipulate any user's token holdings without restriction.
Operationally, this vulnerability presents a catastrophic risk to the OneChain token ecosystem and its users. The contract owner can artificially inflate or deflate any user's token balance, potentially leading to unauthorized wealth creation or destruction of user assets. This capability undermines the fundamental trust in the token system and creates opportunities for financial manipulation and potential theft of funds. The impact extends beyond individual user accounts as it affects the entire token economy, potentially destabilizing market dynamics and token value. The vulnerability also creates opportunities for social engineering attacks where malicious actors might exploit this flaw to manipulate token distributions or create artificial scarcity. Additionally, the flaw compromises the contract's immutability principle, as the owner can modify user balances post-creation, fundamentally altering the expected behavior of the token system.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and overflow protection mechanisms within the smart contract code. The mintToken function must be modified to include explicit checks for arithmetic overflow conditions before performing balance updates, ensuring that all mathematical operations remain within safe bounds. The implementation should incorporate safe math libraries or custom overflow detection routines that prevent the creation of invalid token balances. Contract owners should implement proper access control mechanisms and consider multi-signature ownership arrangements to reduce the risk of single points of failure. Additionally, the code should undergo thorough security auditing and formal verification processes to identify similar vulnerabilities in other functions. Organizations should also consider implementing automated monitoring systems that can detect unusual balance changes or minting operations that might indicate exploitation attempts. The remediation process must align with industry best practices for smart contract security and should follow established frameworks such as the OpenZeppelin security guidelines to ensure comprehensive protection against similar integer overflow vulnerabilities.