CVE-2018-13579 in ForeverCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for ForeverCoin, 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 as CVE-2018-13579 represents a critical integer overflow flaw within the mintToken function of the ForeverCoin Ethereum token smart contract implementation. This vulnerability resides in the core token functionality that allows for the creation and distribution of new tokens within the blockchain ecosystem. The flaw specifically manifests in how the smart contract handles arithmetic operations during token minting processes, creating a scenario where the owner can manipulate user balances beyond normal operational parameters. The integer overflow occurs when the contract attempts to perform calculations that exceed the maximum value that can be stored in the designated data type, causing the value to wrap around to an unexpected lower value. This particular vulnerability directly impacts the integrity of the token economy and user account balances within the ForeverCoin system.
The technical exploitation of this vulnerability stems from the absence of proper input validation and boundary checking within the mintToken function implementation. When the contract owner invokes this function, they can manipulate the underlying integer arithmetic to bypass normal token distribution constraints. The flaw allows for arbitrary balance manipulation by setting specific parameters that trigger the overflow condition, enabling the attacker to assign any desired token value to any user account within the contract. This represents a fundamental failure in the smart contract's defensive programming practices and highlights the importance of implementing comprehensive validation mechanisms. The vulnerability operates at the level of the Ethereum Virtual Machine where integer overflows can be exploited due to the lack of built-in overflow protection in older Solidity versions. According to CWE-190, this vulnerability maps directly to integer overflow conditions that can lead to unexpected behavior in arithmetic operations. The attack vector is particularly dangerous because it requires no external privileges beyond contract ownership, making it a critical concern for token holders and ecosystem participants.
The operational impact of this vulnerability extends far beyond simple balance manipulation, fundamentally compromising the trust and security model of the ForeverCoin token ecosystem. An attacker with contract ownership privileges can arbitrarily inflate or deflate user balances, potentially leading to massive financial losses for token holders and undermining the entire token's economic stability. The vulnerability could enable the creation of unlimited tokens, manipulation of trading dynamics, or even complete theft of user funds through carefully crafted overflow conditions. This flaw directly violates fundamental security principles of decentralized finance applications and could result in regulatory scrutiny for the project. The implications for the broader Ethereum token ecosystem are significant, as this vulnerability demonstrates how seemingly minor implementation flaws can create catastrophic consequences for token economies. Organizations following ATT&CK framework's T1059.006 technique for execution through smart contract manipulation could exploit this vulnerability to alter token distributions. The vulnerability also impacts the contract's compliance with security standards such as those outlined in the Ethereum Smart Contract Security Best Practices document, where proper overflow handling is explicitly recommended.
Mitigation strategies for CVE-2018-13579 require immediate remediation through code modifications and comprehensive security auditing. The primary solution involves implementing proper input validation and boundary checking within the mintToken function to prevent integer overflow conditions from occurring. Developers should utilize SafeMath libraries or similar defensive programming techniques to ensure arithmetic operations remain within valid ranges. The contract should enforce strict limits on token minting operations and implement proper overflow detection mechanisms. Additionally, the contract owner should conduct thorough security audits and consider third-party verification of smart contract code before deployment. Regular code reviews and automated testing using tools such as MythX or Slither can help identify similar vulnerabilities in other contract implementations. The remediation process should also include proper access control measures to limit the privileges of contract owners and implement multi-signature approval processes for critical operations. Organizations should consider implementing emergency stop mechanisms that can freeze token operations if vulnerabilities are discovered. The vulnerability serves as a critical reminder of the importance of adhering to established security frameworks and conducting comprehensive testing before deploying smart contracts to mainnet environments, particularly given the irreversible nature of blockchain transactions and the permanent exposure of smart contract code to public scrutiny.