CVE-2018-13723 in SERVVIZIOToken
Summary
by MITRE
The mintToken function of a smart contract implementation for SERVVIZIOToken, 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 • 02/28/2020
The vulnerability identified as CVE-2018-13723 represents a critical integer overflow flaw within the mintToken function of the SERVVIZIOToken smart contract deployed on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types, creating a pathway for unauthorized manipulation of token balances. The flaw specifically affects the contract's ability to safely increment token quantities during the minting process, allowing malicious actors to exploit the overflow condition to manipulate account balances.
The technical implementation of this vulnerability manifests through the mintToken function's failure to properly validate the addition operation when increasing token balances. When the contract attempts to increment a user's balance by a specified amount, the integer overflow occurs when the addition exceeds the maximum value that can be represented by the underlying integer type. This condition creates a scenario where the balance calculation wraps around to a much smaller value, effectively allowing an attacker to manipulate the target user's balance to arbitrary values. The vulnerability is particularly dangerous because it occurs within the owner-controlled mintToken function, giving the contract owner direct control over the token distribution mechanism.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire token economy and user trust in the SERVVIZIOToken system. An attacker with access to the contract owner account can arbitrarily inflate or deflate user balances, potentially creating a scenario where users lose their tokens or where artificial wealth is created. This manipulation capability undermines the fundamental principles of blockchain-based token systems where transparency and immutability are core requirements. The vulnerability also creates potential for financial loss, as users may find their balances unexpectedly altered, and could lead to complete loss of value in the token ecosystem.
Security mitigations for this vulnerability must address the root cause through proper integer overflow protection mechanisms. The recommended approach involves implementing comprehensive input validation checks before any arithmetic operations within the mintToken function, utilizing safe arithmetic libraries or compiler features that automatically detect and prevent overflow conditions. Additionally, the contract should implement proper access controls and transaction logging to monitor any suspicious balance manipulations. The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and represents a clear violation of the principle of least privilege in blockchain smart contracts. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where an attacker leverages administrative functions to gain control over user assets, potentially leading to financial theft and system compromise within the token ecosystem.