CVE-2018-13208 in MoneyTree
Summary
by MITRE
The sell function of a smart contract implementation for MoneyTree (TREE), 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-2018-13208 represents a critical integer overflow flaw within the MoneyTree (TREE) smart contract implementation on the Ethereum blockchain. This vulnerability specifically affects the sell function of the token contract, creating a scenario where arithmetic operations can produce unexpected results due to insufficient input validation and overflow handling mechanisms. The flaw manifests when the multiplication operation between amount and sellPrice yields a result that equals zero, which fundamentally undermines the contract's ability to accurately process token sales and maintain proper asset accounting for sellers.
The technical execution of this vulnerability stems from the absence of proper integer overflow checks within the sell function implementation. When a user attempts to sell TREE tokens, the contract calculates the value of the sale by multiplying the token amount with the current sellPrice. In scenarios where either the amount or sellPrice variables contain values that, when multiplied together, result in an overflow condition that produces zero, the seller's assets are incorrectly reduced without proper compensation. This behavior directly violates the fundamental principles of secure smart contract development and represents a classic example of CWE-191 Integer Underflow/Overflow, where arithmetic operations fail to properly handle boundary conditions.
The operational impact of this vulnerability extends beyond simple financial loss for individual users, as it fundamentally compromises the integrity of the token's economic model and trust within the MoneyTree ecosystem. Sellers who attempt to liquidate their holdings may find their assets mysteriously reduced to zero or significantly diminished, creating a cascade of potential losses throughout the token's user base. The vulnerability also exposes the contract to potential manipulation by malicious actors who could strategically exploit the overflow condition to drain funds or manipulate the token's market dynamics, representing a significant threat to the platform's financial stability and user confidence.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and overflow protection mechanisms within the smart contract code. The recommended approach involves adding explicit checks to ensure that multiplication operations between amount and sellPrice variables do not produce zero results or overflow conditions, utilizing safe math libraries or implementing manual overflow detection routines as specified in the solidity documentation. Security practitioners should also implement proper error handling and logging mechanisms to detect and respond to potential exploitation attempts, aligning with the ATT&CK framework's approach to detecting and mitigating smart contract vulnerabilities through defensive programming practices. Additionally, comprehensive testing including edge case scenarios and formal verification methods should be employed to ensure that similar vulnerabilities do not exist in other arithmetic operations within the contract's codebase.