CVE-2018-13620 in TripCash
Summary
by MITRE
The mintToken function of a smart contract implementation for TripCash, 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-2018-13620 represents a critical integer overflow flaw within the mintToken function of the TripCash Ethereum smart contract implementation. This vulnerability stems from improper input validation and arithmetic handling within the smart contract code, specifically affecting the token's minting mechanism that allows the contract owner to create new tokens. The flaw manifests when the mintToken function processes token minting operations without adequate overflow checks, creating a scenario where mathematical operations can exceed the maximum value that can be stored in the designated data type, resulting in unexpected behavior and potential manipulation of token balances.
The technical exploitation of this vulnerability occurs through the contract owner's ability to manipulate the mintToken function to set arbitrary user balances to any desired value. This integer overflow creates a condition where the balance calculation wraps around to zero or negative values, or more critically, allows the owner to directly assign any balance value to target users. The underlying issue typically involves unsigned integer variables that do not properly validate against maximum value limits before performing arithmetic operations, making it possible for attackers with owner privileges to manipulate token distributions. This flaw directly violates the fundamental principles of secure smart contract development and represents a classic example of insufficient input validation and arithmetic overflow protection.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token economy and user trust in the TripCash system. An attacker with owner access can create unlimited tokens for themselves or other users, effectively causing inflation of the token supply and potentially enabling fraudulent transactions or unauthorized access to token holdings. The vulnerability also creates opportunities for denial of service attacks where malicious actors could manipulate balances to prevent legitimate transactions or create artificial scarcity. This type of vulnerability significantly undermines the integrity of the token system and can result in financial losses for users who hold TripCash tokens, as well as damage to the reputation of the project and the broader Ethereum ecosystem.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The primary solution involves adding comprehensive input validation and bounds checking to all arithmetic operations, particularly within functions that handle token creation and balance modifications. Developers should implement safe math libraries or utilize established secure coding practices that prevent overflow conditions through explicit checks before performing mathematical operations. The fix should include proper validation of balance values and enforcement of maximum token supply limits to prevent unauthorized minting beyond intended parameters. Additionally, implementing proper access controls and multi-signature requirements for owner functions can reduce the risk of exploitation, while regular security audits and formal verification processes should be conducted to identify and remediate similar vulnerabilities across the entire smart contract implementation. This vulnerability aligns with CWE-191 Integer Underflow/Overflow and relates to ATT&CK technique T1548.001 for privilege escalation through smart contract manipulation, emphasizing the importance of robust input validation and secure coding practices in blockchain environments.