CVE-2018-13584 in yasudem
Summary
by MITRE
The mintToken function of a smart contract implementation for yasudem, 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 • 04/05/2023
The vulnerability identified as CVE-2018-13584 resides within the mintToken function of an Ethereum-based smart contract implementation for the yasudem token. This flaw represents a critical integer overflow vulnerability that fundamentally compromises the security model of the token contract. The vulnerability stems from improper input validation and arithmetic operations within the smart contract code, allowing malicious actors to manipulate token balances through crafted transactions. The integer overflow occurs when the contract attempts to increment token balances without adequate bounds checking, creating a scenario where large values can wrap around to smaller values due to the finite nature of integer representations in blockchain environments.
The technical exploitation of this vulnerability enables an attacker with owner privileges to manipulate the balance of any user account within the token system. This occurs because the mintToken function does not properly validate the parameters passed to it, particularly the amount value that determines how many tokens are minted and credited to a specific address. When an attacker supplies a carefully crafted value that exceeds the maximum limit of the integer type used for balance tracking, the overflow causes the balance to be set to an unexpected value. This behavior aligns with CWE-190, which specifically addresses integer overflow and underflow conditions in software systems. The vulnerability can be exploited to either inflate balances beyond normal limits or to set balances to zero, depending on the specific overflow pattern and the target account.
The operational impact of this vulnerability extends beyond simple balance manipulation and represents a severe threat to the integrity of the token ecosystem. An attacker could potentially drain all tokens from other users by setting their balances to zero, or conversely, create unlimited token supply by manipulating the overflow conditions to generate excessive balances. This vulnerability undermines the fundamental trust model of the token system, as it allows the contract owner to effectively control the distribution of tokens without proper authorization from other participants. The implications are particularly severe in decentralized finance applications where token balances directly correspond to financial assets and voting rights within tokenized governance systems. The vulnerability also demonstrates a failure in the contract's access control mechanisms, as it allows the owner to manipulate all user balances rather than just their own, creating a potential for widespread financial loss across the token ecosystem.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements in smart contract development practices. The primary fix involves implementing proper input validation and bounds checking within the mintToken function to prevent integer overflow conditions from occurring. This includes using safe arithmetic operations that either detect overflow conditions or prevent them through explicit bounds checking. The implementation should incorporate checks that verify that the minted amount does not exceed the maximum allowable value for the integer type being used, and that the resulting balance does not overflow the available storage space. Additionally, developers should consider implementing comprehensive testing procedures including fuzz testing and formal verification methods to identify similar vulnerabilities before deployment. The vulnerability also highlights the importance of following secure coding practices as outlined in the OWASP Secure Coding Practices and aligns with ATT&CK technique T1059.006 for smart contract manipulation, emphasizing the need for thorough security auditing and continuous monitoring of deployed smart contracts. Organizations should also implement proper access control measures and consider multi-signature wallets for contract ownership to reduce the risk of unauthorized manipulation of critical functions.