CVE-2018-13645 in Fiocoin
Summary
by MITRE
The mintToken function of a smart contract implementation for Fiocoin, 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 in CVE-2018-13645 represents a critical integer overflow flaw within the mintToken function of Fiocoin's smart contract implementation on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's token minting mechanism, creating a fundamental security weakness that directly impacts the contract's integrity and user asset protection. The flaw exists at the core level of the token contract's logic, where the mintToken function fails to properly validate or constrain the parameters used to increase user balances, thereby allowing malicious actors to manipulate token distributions.
The technical execution of this vulnerability occurs through the manipulation of integer arithmetic operations within the smart contract's mintToken function. When an attacker invokes this function with carefully crafted parameters, the integer overflow condition is triggered, enabling the contract owner to bypass normal balance increment restrictions. This creates a scenario where the owner can arbitrarily set any user's token balance to an arbitrary value, effectively allowing for unlimited token creation or manipulation of user holdings. The vulnerability manifests as a direct consequence of the contract's failure to implement proper overflow checks, specifically violating the principle of input validation and proper arithmetic boundary enforcement.
From an operational impact perspective, this vulnerability presents severe consequences for both the contract's integrity and user trust within the Fiocoin ecosystem. The ability to set arbitrary user balances effectively allows for unauthorized token distribution, potential theft of funds, or manipulation of token economics. Attackers can exploit this flaw to inflate their own balances or manipulate other users' holdings, undermining the fundamental principles of blockchain-based token systems. The vulnerability also compromises the contract's immutability promise, as the owner can effectively rewrite the token distribution rules post-deployment, creating an attack surface that extends beyond typical smart contract security concerns.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues arising from improper handling of integer arithmetic operations in software systems. This classification emphasizes the fundamental nature of the flaw as a mathematical boundary violation that can be exploited for unauthorized access or manipulation. The attack vector can be mapped to ATT&CK technique T1059.001, Command and Scripting Interpreter, as the vulnerability enables attackers to execute malicious commands through the smart contract's function calls. Additionally, the weakness can be categorized under T1496, Resource Hijacking, as it allows for unauthorized consumption of contract resources through manipulated token minting operations.
Mitigation strategies for this vulnerability require immediate contract-level fixes including the implementation of proper integer overflow checks and input validation mechanisms. Developers should implement require statements that verify parameter boundaries and utilize libraries such as OpenZeppelin's SafeMath to prevent arithmetic overflow conditions. The contract owner should also consider implementing access controls that limit the mintToken function's invocation to trusted parties only, while maintaining comprehensive audit trails of all balance modifications. Regular security audits and formal verification processes should be implemented to prevent similar vulnerabilities in future contract deployments, ensuring that all arithmetic operations within smart contracts properly handle potential overflow conditions through established best practices and industry standards.