CVE-2018-13213 in TravelCoin
Summary
by MITRE
The sell function of a smart contract implementation for TravelCoin (TRV), an Ethereum token, has an integer overflow in which "amount * sellPrice" can be zero, consequently reducing a seller's assets.
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Analysis
by VulDB Data Team • 02/25/2020
The vulnerability identified in CVE-2018-13213 affects the TravelCoin (TRV) smart contract implementation on the Ethereum blockchain, specifically targeting the sell function within the token contract's code. This represents a critical security flaw that directly impacts the financial integrity of users who hold TRV tokens and wish to liquidate their holdings. The vulnerability manifests as an integer overflow condition that occurs during the calculation of asset values when users attempt to sell their tokens, creating a scenario where the mathematical operation "amount * sellPrice" can produce an unexpected zero result, thereby allowing malicious actors to manipulate the token economy.
The technical flaw stems from improper input validation and arithmetic overflow handling within the sell function implementation. When a user attempts to sell TRV tokens, the smart contract calculates the value of the transaction by multiplying the token amount with the current sell price. However, the contract fails to properly validate the multiplication operation, allowing for scenarios where the result of this calculation becomes zero due to integer overflow conditions. This type of vulnerability is categorized under CWE-190, which specifically addresses integer overflow and underflow issues in software implementations. The flaw occurs because the smart contract does not implement proper boundary checks or overflow protection mechanisms before performing arithmetic operations that could potentially exceed the maximum value representable by the data type being used.
The operational impact of this vulnerability extends beyond simple financial loss, as it fundamentally undermines the trust and reliability of the TravelCoin token ecosystem. Users who attempt to sell their tokens may find that their transactions result in zero value transfers, effectively allowing them to lose their entire token holdings without proper compensation. This creates a significant risk for liquidity providers and market participants who depend on the proper functioning of the token's sell mechanism to convert their assets into ether or other supported currencies. The vulnerability also opens the door for potential exploitation by attackers who could manipulate the sell price or token amount to force zero-value transactions, thereby draining user accounts or creating artificial market distortions that could affect the overall token valuation and trading dynamics.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers "Trusted Relationship" and "Evasion of Security Controls" through manipulation of financial systems. The attack vector involves exploiting the smart contract's arithmetic handling to bypass normal transaction validation processes. The vulnerability also demonstrates characteristics of T1072, which involves the compromise of software supply chains or the exploitation of implementation flaws in security-critical systems. Organizations and users should implement immediate mitigations including thorough code audits of all smart contracts, implementation of proper integer overflow protection mechanisms, and deployment of transaction monitoring systems to detect anomalous sell transactions. Additionally, the vulnerability highlights the importance of formal verification techniques and comprehensive testing methodologies for blockchain-based financial applications, as outlined in industry standards such as the Ethereum Smart Contract Best Practices guidelines and the OpenZeppelin security recommendations. The incident serves as a critical reminder of the need for rigorous security assessments before deploying smart contracts to mainnet environments, particularly for high-value financial instruments where the consequences of implementation flaws can be catastrophic for user assets and market confidence.