CVE-2018-13484 in CBRToken
Summary
by MITRE
The mintToken function of a smart contract implementation for CBRToken, 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 vulnerability identified in CVE-2018-13484 represents a critical integer overflow flaw within the mintToken function of the CBRToken smart contract implementation 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. The flaw allows the contract owner to manipulate token balances of arbitrary users by exploiting the overflow condition, creating a fundamental security weakness in the token distribution mechanism.
The technical implementation of this vulnerability occurs when the mintToken function processes token minting operations without proper overflow checks on the balance calculations. When an integer overflow occurs during arithmetic operations, the value wraps around to a smaller number, creating unexpected behavior in the token accounting system. This specific implementation flaw falls under CWE-190, which describes integer overflow and underflow conditions. The vulnerability is particularly dangerous because it directly enables the contract owner to manipulate user balances to arbitrary values, potentially allowing for unlimited token generation or balance manipulation that could undermine the entire token economy.
The operational impact of this vulnerability extends beyond simple balance manipulation, as it fundamentally compromises the integrity of the token system. An attacker with owner privileges could inflate user balances to create artificial wealth, manipulate token distributions, or even create a scenario where the total supply of tokens exceeds the intended maximum. This type of vulnerability aligns with ATT&CK technique T1059.001, which involves the use of command and control protocols, as the overflow enables unauthorized control over token distributions and user accounts. The vulnerability also represents a significant threat to the trust model of the blockchain system, as it allows for manipulation that could be difficult to detect and reverse.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protections within the smart contract code. The mintToken function must incorporate explicit overflow checks using require statements or safe math libraries that prevent arithmetic operations from exceeding data type limits. Additionally, the contract should implement comprehensive access control measures to ensure only authorized entities can perform minting operations. Regular security audits and formal verification of smart contracts should become standard practice to identify and remediate similar vulnerabilities before deployment. The implementation of these measures aligns with industry best practices for blockchain security and helps prevent the exploitation of integer overflow conditions that could lead to financial loss or system compromise.