CVE-2018-13504 in MMCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for MMCoin, 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 as CVE-2018-13504 represents a critical integer overflow flaw within the mintToken function of an Ethereum-based smart contract implementation for MMCoin tokens. 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 fails to properly validate or constrain the numerical values used in the token balance calculations, creating a scenario where arithmetic operations can exceed the maximum representable value for the data type being used.
The technical exploitation of this vulnerability stems from improper input validation and lack of bounds checking within the smart contract's mintToken function. When the contract owner invokes this function with specific parameters, the integer overflow allows manipulation of token balances beyond normal operational limits. This flaw enables attackers to set arbitrary user balances to any desired value, effectively bypassing the normal token distribution and accounting mechanisms. The vulnerability is particularly dangerous because it operates at the contract level where the owner has elevated privileges, making it possible for malicious actors to manipulate the entire token economy and potentially drain resources or create artificial wealth.
From an operational perspective, this vulnerability creates severe implications for the integrity and security of the MMCoin token ecosystem. The ability to set arbitrary user balances means that an attacker could potentially create unlimited tokens, manipulate market dynamics, or gain unauthorized access to funds belonging to other users. The impact extends beyond simple financial loss to include complete compromise of the token's trust model and potential regulatory violations. This type of vulnerability directly violates the fundamental principles of secure smart contract development and can lead to complete loss of user funds and contract functionality.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic operations produce results that exceed the maximum value representable by the data type. This flaw also maps to ATT&CK technique T1210, Exploitation of Remote Services, as it represents an exploitation of a remote smart contract service through manipulation of its core arithmetic functions. Additionally, the vulnerability demonstrates poor secure coding practices and highlights the need for comprehensive input validation and boundary checking in blockchain smart contracts. Organizations should implement rigorous code review processes, formal verification techniques, and automated testing to prevent similar vulnerabilities from occurring in future deployments.
Mitigation strategies should include immediate patching of the smart contract by implementing proper integer overflow protections such as require statements to validate input parameters, using safe math libraries, and implementing comprehensive testing procedures including fuzz testing and formal verification. The contract owner should also consider implementing additional access controls and audit mechanisms to detect unauthorized balance manipulations. Regular security audits and penetration testing of smart contracts are essential to identify and remediate similar vulnerabilities before they can be exploited in production environments.