CVE-2018-13533 in ALUXToken
Summary
by MITRE
The mintToken function of a smart contract implementation for ALUXToken, 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 • 02/27/2020
The CVE-2018-13533 vulnerability represents a critical integer overflow flaw within the mintToken function of the ALUXToken smart contract implementation on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic handling within the token contract's core functionality, creating a fundamental security weakness that directly impacts the contract's integrity and user asset safety. The flaw allows the contract owner to manipulate user balances arbitrarily, effectively bypassing normal token issuance and transfer mechanisms. The vulnerability is classified as an integer overflow according to CWE-190, which specifically addresses issues related to signed integer overflow conditions in software implementations. This particular instance demonstrates how insufficient bounds checking in smart contract code can lead to severe financial consequences for users and the broader ecosystem.
The technical execution of this vulnerability occurs through the mintToken function which fails to properly validate or constrain the parameters passed to it. When the owner invokes this function with maliciously crafted inputs, the integer overflow condition is triggered, allowing for the manipulation of user account balances to arbitrary values. The underlying issue manifests when the contract attempts to increment a token balance beyond the maximum value representable by the integer data type, causing the value to wrap around to a much smaller number or zero. This behavior creates a scenario where the owner can effectively set any user's balance to any desired amount, potentially including negative values or extremely large numbers that could destabilize the entire contract. The vulnerability is particularly dangerous because it operates within the contract's privileged functions, giving the owner unlimited control over user balances without any legitimate justification for such power.
The operational impact of CVE-2018-13533 extends far beyond simple financial manipulation, creating cascading effects throughout the Ethereum token ecosystem and user trust mechanisms. Users who hold ALUXToken face immediate risk of balance manipulation, potentially resulting in loss of funds, unauthorized transfers, or complete account devaluation. The vulnerability undermines the fundamental principles of blockchain-based token systems by allowing central authority manipulation of user assets, which directly contradicts the decentralized trust model that blockchain technologies aim to establish. From an attacker's perspective, this vulnerability aligns with attack patterns described in the MITRE ATT&CK framework under the 'Privilege Escalation' and 'Resource Hijacking' domains, where adversaries exploit contract-level vulnerabilities to gain unauthorized control over resources. The financial implications can be severe, as affected users may lose confidence in the token, leading to market instability, reduced trading volumes, and potential regulatory scrutiny that could impact the entire project's viability and reputation.
Mitigation strategies for CVE-2018-13533 require immediate implementation of robust input validation and arithmetic boundary checks within the smart contract code. The most effective approach involves implementing proper overflow protection mechanisms such as using SafeMath libraries or similar arithmetic libraries that automatically check for overflow conditions before performing operations. The contract owner should also implement comprehensive parameter validation to ensure that all inputs to the mintToken function are within acceptable ranges and that proper bounds checking is enforced. Additionally, regular security audits and formal verification of smart contract code should be conducted to identify similar vulnerabilities before they can be exploited. The vulnerability highlights the importance of following established security best practices in smart contract development and aligns with industry standards that emphasize the need for defensive programming techniques to prevent integer overflow conditions. Organizations should also consider implementing multi-signature wallets for contract ownership and establishing clear governance procedures to prevent unauthorized access to privileged functions that could be exploited to manipulate user balances.