CVE-2018-13581 in TravelCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for TravelCoin (TRV), 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-2018-13581 represents a critical integer overflow flaw within the mintToken function of TravelCoin's smart contract implementation on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types. The flaw allows the contract owner to manipulate token balances by setting them to arbitrary values, effectively bypassing normal transactional constraints and token distribution mechanisms. The integer overflow occurs when the mintToken function performs arithmetic operations without proper bounds checking, enabling malicious actors with owner privileges to manipulate the token supply and user balances at will.
The technical exploitation of this vulnerability places it squarely within CWE-190, which categorizes integer overflow conditions as a fundamental security weakness in software implementations. The operational impact extends beyond simple balance manipulation as it fundamentally compromises the integrity of the token economy. When an attacker with owner access exploits this vulnerability, they can create unlimited tokens, drain other users' balances, or manipulate market dynamics by artificially inflating their own holdings. This type of vulnerability directly violates the principle of least privilege and undermines the trustless nature that blockchain systems are designed to provide, as the owner's elevated privileges can be abused to manipulate the entire token distribution.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.001, representing a code injection attack vector that allows for privilege escalation within the smart contract environment. The attack surface is particularly concerning because it requires only the owner's private key to execute, making it accessible to anyone who has gained access to the contract's administrative credentials. The vulnerability creates a persistent threat that can be exploited multiple times, potentially allowing for the creation of unlimited tokens and the manipulation of user balances to achieve arbitrary financial outcomes. The lack of proper input validation in the mintToken function means that any attempt to mint tokens beyond normal limits will result in unexpected behavior due to the overflow condition, which can be leveraged to achieve malicious outcomes.
The mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protections within the smart contract code. Developers must implement explicit bounds checking before any arithmetic operations in the mintToken function, ensuring that all inputs are validated against maximum and minimum value limits. The contract should utilize SafeMath libraries or similar protective mechanisms that automatically check for overflow conditions and revert transactions when such conditions occur. Additionally, the contract owner should implement proper access control measures and consider implementing multi-signature wallets for critical operations to reduce the risk of unauthorized access. Regular security audits and formal verification of smart contract code should become standard practice to identify and remediate similar vulnerabilities before they can be exploited in production environments. The vulnerability also highlights the importance of proper code review processes and adherence to secure coding practices specifically tailored for blockchain development environments where financial assets are at risk.