CVE-2018-13695 in CTest7
Summary
by MITRE
The mint function of a smart contract implementation for CTest7, 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 described in CVE-2018-13695 represents a critical integer overflow flaw within the mint function of a smart contract implementation for the CTest7 Ethereum token. This type of vulnerability falls under the CWE-190 category of integer overflow or wraparound, which occurs when an arithmetic operation attempts to create a value that exceeds the maximum value that can be stored within the allocated storage space. The flaw specifically affects the mint function, which is designed to create new tokens and distribute them to users within the Ethereum blockchain ecosystem.
The technical implementation of this vulnerability stems from inadequate input validation and overflow checking within the smart contract's mint function. When the contract owner invokes the mint function to create new tokens, the code fails to properly validate the input parameters, particularly those related to the token amount being minted. This oversight allows an attacker with owner privileges to manipulate the minting process in such a way that they can directly control the balance of any user account within the token contract. The integer overflow occurs when the contract attempts to increment a balance value beyond its maximum representable limit, causing the value to wrap around to zero or a negative value, which can then be exploited to set arbitrary balances.
The operational impact of this vulnerability is severe and far-reaching within the Ethereum token ecosystem. An attacker with contract ownership privileges can exploit this flaw to manipulate token distributions and potentially create unlimited tokens within the system. This creates a fundamental breach of the token's economic model and can lead to significant financial losses for other token holders who may experience dilution of their holdings. The vulnerability essentially allows for unauthorized token creation and balance manipulation, which undermines the core principles of blockchain token economics and trustless systems. Additionally, this flaw can enable various malicious activities including but not limited to creating artificial market conditions, manipulating token prices, and potentially enabling theft of funds from other users' accounts.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security practices within smart contract development. The primary fix involves implementing proper integer overflow checks using modern Solidity practices, including the use of require statements to validate input parameters and ensure that balance calculations remain within acceptable bounds. Developers should employ SafeMath libraries or similar overflow protection mechanisms to prevent arithmetic operations from producing unexpected results. The contract should also implement proper access controls and audit trails to monitor and restrict mint function usage. From a broader security perspective, this vulnerability highlights the importance of comprehensive smart contract auditing and the adoption of security standards such as those outlined in the OpenZeppelin security guidelines. Organizations should also consider implementing multi-signature wallet systems for contract ownership and regular security assessments to prevent similar vulnerabilities from being introduced into blockchain applications. The ATT&CK framework categorizes this type of vulnerability under the T1059.001 technique of command and control through smart contract manipulation, emphasizing the need for robust input validation and access control mechanisms in blockchain environments.