CVE-2018-13774 in Bitstarti
Summary
by MITRE
The mintToken function of a smart contract implementation for Bitstarti, 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 in CVE-2018-13774 represents a critical integer overflow flaw within the mintToken function of Bitstarti's Ethereum token smart contract implementation. This vulnerability resides in the core token minting mechanism that allows contract owners to create new tokens and distribute them to users. The integer overflow occurs when the contract attempts to increment token balances without proper bounds checking, creating a condition where arithmetic operations can wrap around to unexpected values. Such flaws are particularly dangerous in decentralized applications where financial assets are managed through automated smart contracts, as they can be exploited to manipulate token distributions and potentially drain contract resources.
The technical exploitation of this vulnerability stems from the absence of input validation and overflow protection mechanisms within the mintToken function. When an attacker or contract owner invokes this function with carefully crafted parameters, the integer overflow allows them to manipulate the balance of any user account to an arbitrary value. This includes the potential to set balances to extremely large values or even zero, effectively allowing unauthorized token manipulation. The vulnerability directly maps to CWE-190, which defines integer overflow and wraparound conditions, and represents a classic example of how insufficient input validation can lead to severe financial consequences in blockchain environments. The lack of proper boundary checks in Ethereum smart contracts makes such vulnerabilities particularly dangerous because they can be exploited without requiring complex attack vectors and can result in immediate financial loss.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass broader security implications for the entire token ecosystem. Contract owners who possess the ability to exploit this vulnerability can effectively control token distribution, potentially creating unlimited tokens or redistributing existing tokens to malicious addresses. This capability undermines the fundamental principles of token economics and can lead to complete loss of user funds. The vulnerability also affects trust in the platform, as users cannot rely on the integrity of their token balances. From an attacker perspective, this represents a high-value target within the attack surface since it provides direct control over token economics without requiring complex multi-stage attacks or sophisticated exploitation techniques. The vulnerability's impact is further amplified by the fact that it operates at the contract level, meaning that any user interaction with the mintToken function can be manipulated to achieve unauthorized outcomes.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protections within the smart contract code. The most effective approach involves implementing comprehensive input validation and boundary checking before any arithmetic operations occur in the mintToken function. This includes using safe math libraries that automatically detect and prevent overflow conditions, such as OpenZeppelin's SafeMath implementation, which is widely recognized as a standard security practice in Ethereum smart contract development. Additionally, contract owners should implement proper access controls and audit mechanisms to monitor and restrict who can invoke mintToken functions. The remediation process must also include thorough code reviews and security auditing to identify similar vulnerabilities throughout the contract codebase, as integer overflows often occur in multiple locations within complex smart contracts. Organizations should also consider implementing automated testing frameworks that specifically target integer overflow conditions to prevent similar vulnerabilities from being introduced in future updates or new contract deployments.