CVE-2018-13224 in Virtual Energy Units
Summary
by MITRE
The sell function of a smart contract implementation for Virtual Energy Units (VEU) (Contract Name: VEU_TokenERC20), 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-2018-13224 affects the VEU_TokenERC20 smart contract implementation for Virtual Energy Units, representing a critical integer overflow flaw within the sell function that fundamentally compromises asset integrity. This vulnerability resides in the core token functionality where the sell operation processes transactions involving virtual energy units, creating a scenario where mathematical calculations can produce unexpected results due to improper handling of numeric overflow conditions.
The technical flaw manifests when the sell function executes the calculation "amount * sellPrice" where the multiplication operation can result in zero despite non-zero input values. This occurs because the smart contract does not properly validate or sanitize the multiplication result before proceeding with asset transfers, creating an exploitable condition where sellers can manipulate their token holdings. The vulnerability directly maps to CWE-191, which describes integer underflow/overflow conditions, and specifically aligns with the broader category of CWE-682, involving incorrect use of arithmetic operations that can produce unexpected results. The implementation fails to account for potential overflow scenarios during the multiplication of token amounts with pricing factors, allowing for malicious or accidental manipulation of transaction outcomes.
The operational impact of this vulnerability extends beyond simple financial loss, as it fundamentally undermines the trust and integrity of the token ecosystem. When sellers attempt to exchange their VEU tokens for ether or other assets, the zero-result scenario can lead to complete asset loss or manipulation of the token distribution model. Attackers can exploit this flaw to either completely eliminate their token holdings while receiving compensation, or to artificially inflate their asset values by manipulating the calculation results. This vulnerability directly impacts the security posture of the Ethereum-based token system and represents a significant risk to all parties involved in token transactions, particularly those relying on the contract's integrity for asset management and value exchange operations.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow checks and validation mechanisms within the smart contract code. The recommended approach involves adding explicit bounds checking before arithmetic operations, implementing safe math libraries, and ensuring that all multiplication operations are validated against potential overflow conditions. Security practitioners should enforce the use of established secure coding practices and conduct thorough code reviews focusing on mathematical operations within smart contracts. Additionally, the contract should implement proper input validation and error handling mechanisms that prevent zero-value transactions from being processed, while also ensuring that all asset transfers are properly verified against expected calculation results. The remediation aligns with ATT&CK technique T1548.003, which involves privilege escalation through code injection or modification, as this vulnerability represents a fundamental flaw in the contract's mathematical operations that could be exploited to gain unauthorized access to token assets. Organizations should also consider implementing automated testing frameworks that specifically target integer overflow conditions and mathematical operation validation to prevent similar issues in future deployments.