CVE-2018-13228 in Crowdnext
Summary
by MITRE
The sell function of a smart contract implementation for Crowdnext (CNX), 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-2018-13228 affects the Crowdnext (CNX) smart contract implementation on the Ethereum blockchain, specifically within the sell function of the token contract. This represents a critical security flaw that directly impacts the integrity of financial transactions and asset management within the decentralized application. The vulnerability manifests as an integer overflow condition that occurs during the calculation process when determining the value of assets being sold, creating a scenario where legitimate transactions can be manipulated or rendered ineffective due to mathematical miscalculations.
The technical flaw stems from improper handling of arithmetic operations within the smart contract's sell function where the multiplication of "amount * sellPrice" can result in an integer overflow condition. When the product of these two values exceeds the maximum representable value for the data type being used, the result wraps around to zero or another unintended value. This overflow condition specifically impacts the calculation of proceeds from token sales, allowing attackers to manipulate the transaction outcomes in ways that benefit malicious actors while causing legitimate sellers to lose assets. The vulnerability operates at the core level of the contract's financial logic, undermining the fundamental trust mechanisms that smart contracts are designed to provide.
The operational impact of this vulnerability extends beyond simple financial loss to encompass broader security implications for the entire Crowdnext ecosystem. Sellers who attempt to liquidate their tokens may find their assets reduced or completely lost due to the zero result from the overflow condition, effectively creating a mechanism for unauthorized asset draining. This type of vulnerability directly undermines the confidence users place in smart contract-based financial systems and can lead to significant economic losses for participants in the network. The vulnerability is particularly dangerous because it operates silently within the contract's logic, making detection difficult and potentially allowing attackers to exploit it repeatedly without immediate detection.
From a cybersecurity perspective, this vulnerability aligns with CWE-191, which specifically addresses integer underflow and overflow conditions, and can be categorized under ATT&CK technique T1499.004 for malicious use of cryptographic tokens. The flaw demonstrates a classic example of inadequate input validation and arithmetic operation handling within smart contracts, representing a fundamental security oversight in the contract development process. Organizations implementing similar token contracts should conduct thorough security audits and employ rigorous testing methodologies including formal verification techniques to prevent such mathematical errors from compromising asset integrity.
Mitigation strategies for this vulnerability require immediate patching of the smart contract implementation to properly handle integer arithmetic operations through bounds checking and overflow protection mechanisms. Developers should implement explicit validation checks before performing multiplication operations to ensure that results remain within acceptable ranges. Additionally, comprehensive testing including edge case scenarios and stress testing of arithmetic operations should become standard practice in smart contract development cycles. The use of established secure coding libraries and frameworks specifically designed for blockchain environments can help prevent such mathematical errors while implementing robust error handling mechanisms that gracefully manage exceptional conditions rather than allowing them to corrupt transaction outcomes.