CVE-2018-13546 in CCASH
Summary
by MITRE
The mintToken function of a smart contract implementation for CCASH, 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-2018-13546 represents a critical integer overflow flaw within the mintToken function of the CCASH Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic operations that fail to account for boundary conditions in the underlying blockchain smart contract code. The flaw allows malicious actors with contract ownership privileges to manipulate token balances by exploiting the overflow condition, potentially enabling unauthorized balance manipulation and financial loss for token holders. The vulnerability directly maps to CWE-191, which specifically addresses integer underflow and overflow conditions, and demonstrates how improper handling of numeric data types can lead to severe security implications in decentralized applications.
The technical execution of this vulnerability occurs through the mintToken function's failure to validate input parameters and implement proper overflow checks during balance calculations. When the contract owner invokes this function with manipulated parameters, the integer overflow condition allows them to set arbitrary user balances to predetermined values, effectively bypassing normal token minting and distribution mechanisms. This flaw operates at the core of the smart contract's financial logic and demonstrates a fundamental lack of input sanitization and boundary checking that is essential for secure blockchain implementations. The vulnerability's impact extends beyond simple balance manipulation as it can be leveraged to create infinite token supply conditions or manipulate token distribution to favor specific addresses.
The operational implications of this vulnerability are severe and multifaceted within the Ethereum blockchain ecosystem. Contract owners can exploit this flaw to artificially inflate token balances for malicious addresses, potentially leading to market manipulation, theft of funds, or disruption of token economics. The vulnerability also creates trust issues within the token community as it demonstrates a fundamental flaw in the contract's security model that could be exploited by attackers who gain ownership privileges. Additionally, the impact extends to token value stability and investor confidence, as such vulnerabilities can cause immediate market disruption and may require emergency contract upgrades or token burns to address the security breach. The vulnerability's exploitation aligns with ATT&CK technique T1499.004, which covers evasion through modification of system processes, and demonstrates how smart contract security flaws can be leveraged for financial gain.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and overflow protection mechanisms within the smart contract code. Developers should implement explicit bounds checking and use safe arithmetic libraries that prevent integer overflow conditions, particularly when dealing with balance calculations and token minting operations. The recommended approach includes utilizing established secure coding practices such as the OpenZeppelin SafeMath library or similar overflow protection mechanisms that are widely adopted in the Ethereum ecosystem. Additionally, regular security audits and formal verification of smart contracts should be implemented to identify similar vulnerabilities before they can be exploited. Contract owners should also consider implementing multi-signature ownership controls and time locks for critical functions to reduce the risk of unauthorized exploitation. The vulnerability serves as a reminder of the critical importance of secure smart contract development practices and the need for comprehensive security testing before deployment of any blockchain-based financial applications.