CVE-2018-13588 in Code47
Summary
by MITRE
The mintToken function of a smart contract implementation for Code47 (C47), 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 • 02/27/2020
The vulnerability identified in CVE-2018-13588 represents a critical integer overflow flaw within the mintToken function of the Code47 (C47) Ethereum token smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's codebase, creating a fundamental security weakness that directly impacts the token's integrity and user fund protection. The flaw exists in the contract's core functionality where the mintToken function fails to properly validate or constrain the values being processed during token creation operations, allowing for potentially malicious manipulation of user balances.
The technical execution of this vulnerability occurs when the contract owner invokes the mintToken function with manipulated parameters that cause integer overflow conditions. This overflow enables the attacker to manipulate the internal accounting system of the token contract, specifically targeting the balance storage mechanism for arbitrary user accounts. The vulnerability manifests as a direct consequence of improper bounds checking and lack of overflow detection mechanisms within the smart contract's arithmetic operations, which is a well-documented pattern in blockchain security vulnerabilities. According to CWE-190, this represents an integer overflow vulnerability that occurs when a program performs arithmetic operations on signed integers without proper overflow checking, making it susceptible to exploitation through crafted input values.
The operational impact of this vulnerability is severe and far-reaching for the Code47 token ecosystem and its users. An attacker with owner privileges can arbitrarily manipulate user balances, potentially leading to unauthorized token distribution, account manipulation, and fund theft. The vulnerability allows for the creation of unlimited tokens for specific accounts, effectively enabling the attacker to drain the token supply or create artificial inflation. This compromise directly affects the token's economic model and trust mechanisms, as users cannot rely on accurate balance reporting. The vulnerability also poses risks to the broader Ethereum ecosystem by demonstrating the potential for similar flaws in other token implementations and highlighting the need for rigorous smart contract security auditing.
Mitigation strategies for this vulnerability require immediate remediation of the smart contract code to implement proper integer overflow protection mechanisms. The fix should include comprehensive input validation, explicit bounds checking, and the use of safe arithmetic libraries such as OpenZeppelin's SafeMath implementation to prevent overflow conditions. Contract owners must conduct thorough security audits and implement proper access control mechanisms to limit the privileges of contract owners and prevent unauthorized manipulation. Additionally, the vulnerability underscores the importance of adhering to established security frameworks and best practices such as those outlined in the Ethereum Smart Contract Security Best Practices, which recommend defensive programming techniques including overflow protection, proper error handling, and comprehensive testing procedures. The remediation process should also involve updating the contract's ownership mechanisms and implementing multi-signature approval processes for critical operations to prevent single points of failure and unauthorized access.
The vulnerability demonstrates how basic arithmetic operations in smart contracts can become security risks when proper safeguards are not implemented, aligning with ATT&CK technique T1499.004 which describes the exploitation of vulnerabilities in smart contracts to manipulate token balances and financial outcomes. This case study emphasizes the critical need for security-conscious development practices and the integration of security testing throughout the smart contract development lifecycle. The flaw also highlights the importance of formal verification methods and automated security analysis tools that can detect such vulnerabilities during the development phase rather than after deployment, as the latter often results in costly remediation efforts and loss of user trust in the affected token ecosystem.