CVE-2018-13146 in LEF
Summary
by MITRE
The mintToken, buy, and sell functions of a smart contract implementation for LEF, an Ethereum token, have an integer overflow.
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Analysis
by VulDB Data Team • 02/25/2020
The vulnerability identified as CVE-2018-13146 represents a critical integer overflow flaw within the smart contract implementation of LEF token on the Ethereum blockchain. This vulnerability affects three core functions: mintToken, buy, and sell, which are fundamental to the token's operation and value creation mechanisms. The flaw stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types, creating opportunities for malicious actors to manipulate contract state and potentially steal funds or disrupt operations. The vulnerability directly maps to CWE-190, Integer Overflow or Wraparound, which is classified as a common weakness in software development that frequently manifests in blockchain smart contracts due to insufficient bounds checking. This type of vulnerability is particularly dangerous in decentralized applications because the immutable nature of blockchain transactions means that exploited flaws can have permanent consequences without the ability to patch or rollback.
The technical implementation of this vulnerability occurs when the smart contract performs arithmetic operations without proper overflow checks on integer values. In Ethereum smart contracts, integer overflows happen when an arithmetic operation attempts to store a value that exceeds the maximum value that can be represented by the data type. When the mintToken function processes token creation, or when buy and sell functions calculate token amounts or balances, the lack of overflow protection allows attackers to input values that cause the integers to wrap around to zero or negative values. This creates a scenario where malicious users can manipulate token supply, manipulate account balances, or bypass purchase limits. The vulnerability is particularly concerning because it affects the core economic functions of the token, potentially allowing attackers to create unlimited tokens or manipulate pricing mechanisms to gain unfair advantages in the token ecosystem.
The operational impact of this vulnerability extends beyond simple financial loss to encompass the complete integrity and trustworthiness of the LEF token ecosystem. Attackers could exploit the integer overflow to mint unlimited tokens, manipulate their own account balances to gain unfair advantages in trading, or disrupt the normal functioning of the token's economic model. This type of vulnerability can lead to significant market manipulation, loss of investor confidence, and potential total loss of funds within the token's ecosystem. The vulnerability affects all users who interact with the token through the affected functions, making it a systemic risk rather than an isolated incident. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1587.001 for developing capabilities and T1499.004 for unauthorized access to resources, as it provides a method for compromising the token's economic integrity and potentially stealing funds through manipulation of the underlying smart contract logic.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protections within the smart contract code. Developers must implement explicit bounds checking and use safe arithmetic operations that either revert transactions on overflow or utilize libraries specifically designed to prevent integer overflows. The recommended approach involves using modern Solidity versions with overflow protection features or implementing require statements that validate input parameters before performing arithmetic operations. Additionally, comprehensive testing including fuzz testing and formal verification should be conducted to identify similar vulnerabilities in other functions of the smart contract. The vulnerability highlights the importance of following secure coding practices as outlined in the OWASP Secure Coding Practices and emphasizes the need for thorough code review processes specifically tailored for blockchain applications. Regular security audits and the implementation of automated testing frameworks can help prevent similar vulnerabilities from being introduced in future updates or new smart contract deployments.