CVE-2018-13490 in FILM
Summary
by MITRE
The mintToken function of a smart contract implementation for FILM, 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-2018-13490 represents a critical integer overflow flaw within the mintToken function of the FILM Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types. The flaw allows the contract owner to manipulate token balances in ways that exceed normal operational boundaries, creating a potential pathway for unauthorized value manipulation within the token ecosystem.
The technical root cause of this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions where an operation on a signed or unsigned integer causes the result to exceed the maximum value that can be represented by the data type. In the context of Ethereum smart contracts, this manifests when the mintToken function performs arithmetic operations without proper bounds checking, enabling the owner to exploit the overflow behavior to set arbitrary user balances. The vulnerability exists because the contract does not validate whether the addition operation will exceed the maximum value permitted for the token balance data type, typically a uint256 in Solidity implementations.
The operational impact of this vulnerability extends beyond simple balance manipulation, creating significant security implications for the entire FILM token ecosystem. An attacker with owner privileges can arbitrarily set any user's token balance to any value, potentially including extremely large amounts that could disrupt the token's economic model. This capability could enable the creation of infinite tokens, manipulation of token distributions, or the establishment of artificial market conditions that could undermine the token's value proposition. The vulnerability also represents a direct threat to the principle of decentralized trust, as it allows the contract owner to override normal tokenomics and user expectations.
From a cybersecurity perspective, this vulnerability demonstrates the importance of rigorous input validation and the application of defensive programming practices in smart contract development. The ATT&CK framework for blockchain environments would classify this as a privilege escalation technique, where an attacker with owner-level access exploits a flaw in the contract's logic to gain unauthorized control over token distributions. Organizations should implement comprehensive smart contract auditing processes that include systematic testing for integer overflow conditions, particularly in functions that manipulate state variables such as balances, allowances, and token supplies. The vulnerability underscores the necessity of employing automated tools and manual code reviews to identify such flaws before deployment, as the immutable nature of blockchain contracts makes post-deployment remediation extremely difficult and costly.
Mitigation strategies should focus on implementing proper integer overflow protection mechanisms including explicit bounds checking, the use of SafeMath libraries, and comprehensive unit testing of arithmetic operations within smart contracts. Additionally, contract owners should consider implementing multi-signature wallet requirements for critical functions, thereby reducing the risk associated with single points of failure. Regular security audits and continuous monitoring of contract behavior can help detect anomalous patterns that might indicate exploitation attempts. The incident highlights the critical importance of adhering to established security frameworks and best practices in blockchain development to prevent such fundamental flaws from compromising entire token ecosystems.