CVE-2018-13194 in TongTong Coin
Summary
by MITRE
The mintToken function of a smart contract implementation for TongTong Coin (TTCoin), 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 • 02/25/2020
The vulnerability identified in CVE-2018-13194 represents a critical integer overflow flaw within the mintToken function of the TongTong Coin (TTCoin) smart contract deployed on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's token minting mechanism, creating a scenario where the contract owner can manipulate user balances arbitrarily. The flaw exists due to the absence of proper bounds checking when performing arithmetic operations on token amounts, allowing malicious actors with contract ownership privileges to execute unauthorized balance modifications.
The technical implementation of this vulnerability occurs through the mintToken function which fails to validate the parameters passed to it, particularly the amount parameter that determines how many tokens to mint for a specific user. When the contract performs arithmetic operations without proper overflow checks, it creates conditions where large values can wrap around to smaller values, enabling the contract owner to manipulate the token supply and user balances. This type of vulnerability is classified under CWE-190 as "Integer Overflow or Wraparound" and represents a fundamental flaw in the contract's mathematical operations handling. The vulnerability can be exploited through direct contract calls where the owner manipulates the amount parameter to achieve desired balance values, potentially resulting in unlimited token creation or arbitrary balance manipulation.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial loss, contract integrity compromise, and systemic risks within the token ecosystem. An attacker with ownership privileges can increase their own token holdings indefinitely, potentially leading to massive dilution of other token holders' investments and complete control over the token distribution. The vulnerability also creates trust issues within the community as users cannot rely on the integrity of their token balances. From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.006 for smart contract exploitation and T1548.001 for privilege escalation. The impact is particularly severe because it allows for direct financial gain through unauthorized minting operations, potentially resulting in total loss of value for legitimate token holders.
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 protection mechanisms including explicit bounds checking, using safe arithmetic libraries such as OpenZeppelin's SafeMath, and conducting comprehensive input validation for all function parameters. Contract developers should also implement proper access control measures and audit all arithmetic operations within smart contracts. Additionally, regular security audits and formal verification processes should be implemented to identify similar vulnerabilities in the codebase. The vulnerability demonstrates the critical importance of adhering to security best practices in smart contract development as outlined in the Ethereum Smart Contract Security Best Practices and the OWASP Smart Contract Security Verification Standard, which emphasize the need for comprehensive testing and validation of all mathematical operations within blockchain applications.