CVE-2018-13225 in MyYLC
Summary
by MITRE
The sell function of a smart contract implementation for MyYLC, 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-2018-13225 represents a critical integer overflow flaw within the sell function of MyYLC Ethereum token smart contract implementation. This vulnerability stems from improper input validation and arithmetic operations that fail to account for potential overflow conditions in the underlying blockchain smart contract code. The specific flaw occurs when the product of amount and sellPrice calculations results in zero, which fundamentally undermines the tokenomics and financial integrity of the contract's trading mechanism. The vulnerability directly violates the principles of secure smart contract development as outlined in the CWE-190 category for integer overflow/underflow conditions.
The technical execution of this vulnerability relies on manipulating the sell function parameters to trigger arithmetic overflow conditions within the Ethereum Virtual Machine. When a seller attempts to redeem tokens through the sell function, the contract performs the calculation amount * sellPrice to determine the value of tokens being sold. If either the amount or sellPrice parameter is set to zero, or if the multiplication results in an overflow condition that produces zero, the seller receives zero value for their tokens. This condition effectively allows attackers to manipulate the sell transaction to gain an unfair advantage by reducing their asset exposure while maintaining the appearance of a legitimate transaction. The vulnerability operates at the core of the token's economic model and directly impacts the fundamental trust mechanism within the smart contract system.
The operational impact of this vulnerability extends beyond simple financial loss to encompass broader implications for smart contract security and user confidence in decentralized applications. Attackers can exploit this condition to manipulate token redemption values, potentially causing significant financial distortion within the token ecosystem. The vulnerability creates an opportunity for malicious actors to systematically reduce their asset exposure while maintaining the appearance of legitimate transactions, thereby undermining the integrity of the token's economic model. This flaw particularly affects the token's liquidity and trading mechanisms, as it allows for manipulation of the sell price calculation that could lead to systematic devaluation of the token or create artificial market distortions. The vulnerability also impacts the contract's ability to accurately track and process token transfers, potentially leading to accounting discrepancies that could affect all users of the token.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The most effective approach involves implementing comprehensive input validation and arithmetic overflow checks before any mathematical operations are performed, particularly in the sell function where the vulnerability manifests. Developers should employ established secure coding practices such as using safe math libraries that automatically detect and prevent overflow conditions, or implementing explicit overflow checks using require statements that validate mathematical operations before execution. Additionally, the contract should implement proper boundary checking for all input parameters, ensuring that amount and sellPrice values fall within acceptable ranges before processing transactions. This vulnerability aligns with ATT&CK technique T1059.001 for execution through smart contract manipulation and demonstrates the importance of following secure coding standards as recommended by the Ethereum Smart Contract Security Best Practices guidelines. The fix should also include comprehensive testing of edge cases including zero values, maximum integer values, and boundary conditions to ensure robust protection against similar vulnerabilities in the future.