CVE-2018-13510 in Welfare Token Fund
Summary
by MITRE
The mintToken function of a smart contract implementation for Welfare Token Fund (WTF), 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-2018-13510 represents a critical integer overflow flaw within the mintToken function of the Welfare Token Fund (WTF) smart contract deployed on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's token minting mechanism, creating a fundamental security weakness that directly impacts the contract's integrity and user asset safety. The flaw allows the contract owner to manipulate token balances of arbitrary users through controlled overflow conditions, effectively bypassing normal token distribution and transfer restrictions.
The technical implementation of this vulnerability manifests through improper handling of unsigned integer arithmetic operations within the mintToken function. When the contract attempts to increment token balances or perform arithmetic operations that exceed the maximum value representable by the integer data type, the overflow occurs without proper boundary checking. This behavior violates the fundamental principles of secure smart contract development as outlined in the Ethereum Smart Contract Security Best Practices and aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses vulnerabilities arising from improper integer handling in software systems. The overflow condition creates a scenario where the balance calculation wraps around to an unexpectedly low value, enabling the contract owner to manipulate user balances to arbitrary values.
The operational impact of this vulnerability extends beyond simple financial manipulation to encompass potential systemic risks within the token economy. An attacker with owner privileges can effectively drain user funds, create artificial inflation, or manipulate token distribution to gain unfair advantages in token-based governance or trading systems. This vulnerability directly enables privilege escalation attacks and can be classified under the ATT&CK framework's Privilege Escalation technique, where an attacker leverages legitimate administrative functions to gain unauthorized access to resources. The implications are particularly severe for the Welfare Token Fund ecosystem, as it undermines the trustless nature of the blockchain system and allows for unauthorized balance manipulation that could affect the entire token distribution model.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and integer overflow protection mechanisms within the smart contract code. The contract should implement explicit bounds checking and use safe arithmetic libraries that prevent overflow conditions through built-in overflow detection. Additionally, the contract owner should implement proper access controls and consider using multi-signature wallets for administrative functions to reduce the attack surface. The solution must align with the Ethereum Improvement Proposal standards and follow the secure coding practices recommended by the OpenZeppelin security team. Regular security audits and formal verification of smart contract code should become standard practice to prevent similar vulnerabilities from being introduced in future implementations, as this type of flaw represents a common pattern in blockchain smart contract security that requires systematic defensive programming approaches.