CVE-2018-13759 in BIGCAdvancedToken
Summary
by MITRE
The mintToken function of a smart contract implementation for BIGCAdvancedToken, 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.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 03/03/2020
The vulnerability described in CVE-2018-13759 represents a critical integer overflow flaw within the mintToken function of the BIGCAdvancedToken smart contract implementation on the Ethereum blockchain. This vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which occurs when an operation on an integer value exceeds the maximum representable value for that data type. The specific implementation flaw allows the contract owner to manipulate token balances through a maliciously crafted mintToken call that exploits the underlying integer arithmetic.
The technical exploitation of this vulnerability stems from improper input validation and lack of overflow checking within the mintToken function. When the owner invokes this function with carefully crafted parameters, the integer overflow enables them to manipulate the token balance of any user account to an arbitrary value. This occurs because the smart contract does not properly validate the input parameters before performing arithmetic operations that could result in wraparound behavior. The vulnerability is particularly dangerous because it directly affects the core token economics and can be used to create unlimited tokens or manipulate existing balances without detection.
The operational impact of this vulnerability extends far beyond simple balance manipulation, as it fundamentally compromises the integrity of the token economy and can lead to severe financial losses for users and the project itself. An attacker with owner privileges can artificially inflate token balances, potentially enabling them to drain the contract's token reserves or manipulate market dynamics. This type of vulnerability can be exploited to create a scenario where the total supply of tokens becomes corrupted, leading to unpredictable behavior in the token system. The attack vector aligns with ATT&CK technique T1059.006 for Smart Contract Exploitation, where adversaries leverage code execution flaws to manipulate system state.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protections through comprehensive input validation and the use of safe arithmetic operations. Smart contract developers should implement checks that verify arithmetic operations do not exceed maximum integer values before executing any balance modifications. The recommended approach involves using libraries such as OpenZeppelin's SafeMath or similar overflow protection mechanisms that automatically prevent arithmetic overflow conditions. Additionally, the contract should enforce strict access controls and validate all inputs to the mintToken function, ensuring that the owner cannot manipulate token balances beyond the intended limits. Regular security audits and formal verification of smart contract code should be conducted to identify similar vulnerabilities in other functions or contracts within the same codebase.