CVE-2018-13761 in NetkillerAdvancedTokenAirDrop
Summary
by MITRE
The mintToken function of a smart contract implementation for NetkillerAdvancedTokenAirDrop, 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 • 03/03/2020
The vulnerability identified as CVE-2018-13761 represents a critical integer overflow flaw within the mintToken function of the NetkillerAdvancedTokenAirDrop smart contract deployed on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's token minting mechanism, creating a severe security risk that directly impacts the contract's integrity and user fund safety. The flaw allows the contract owner to manipulate token balances of arbitrary users by exploiting the underlying integer overflow condition, effectively granting unauthorized control over token distribution and potentially enabling fraudulent activities.
The technical implementation of this vulnerability occurs when the mintToken function processes token minting operations without proper bounds checking or overflow detection mechanisms. In Ethereum smart contracts, integer overflows occur when arithmetic operations exceed the maximum value that can be stored in the designated data type, causing the value to wrap around to zero or negative values. The specific flaw in this contract implementation likely involves an unsigned integer variable that can be incremented beyond its maximum representable value, allowing an attacker with owner privileges to manipulate the token supply and user balances at will. This type of vulnerability falls under the CWE-190 category of integer overflow or wraparound, which is classified as a critical weakness in software security.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token ecosystem and user trust in the platform. When the contract owner can set any user's balance to arbitrary values, they gain the ability to create unlimited tokens, manipulate market prices, or transfer funds without proper authorization. This creates a scenario where users may lose their token holdings or experience unexpected behavior in their wallet balances, undermining the fundamental principles of blockchain security and decentralization. The vulnerability also enables potential attack vectors such as front-running, manipulation of token distribution events, or creation of artificial market conditions that could result in significant financial losses for token holders.
Mitigation strategies for this vulnerability require immediate contract redeployment with proper overflow protection mechanisms and comprehensive security auditing of all smart contract functions. The recommended approach involves implementing explicit bounds checking, using safe math libraries that prevent overflow conditions, and conducting thorough code reviews to identify similar vulnerabilities across all contract functions. Organizations should adopt the principle of least privilege by ensuring that contract owners have limited capabilities and that all operations undergo rigorous testing before deployment. Additionally, implementing automated security scanning tools and formal verification methods can help detect such vulnerabilities during development phases. The ATT&CK framework categorizes this type of vulnerability under the software supply chain attacks category, emphasizing the importance of secure development practices and continuous monitoring of deployed smart contracts to prevent exploitation of such fundamental flaws in blockchain applications.