CVE-2018-13716 in sexhdsolo
Summary
by MITRE
The mintToken function of a smart contract implementation for sexhdsolo, 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 • 02/28/2020
The vulnerability identified as CVE-2018-13716 represents a critical integer overflow flaw within the mintToken function of an Ethereum token smart contract implementation known as sexhdsolo. This vulnerability stems from inadequate input validation and arithmetic handling within the smart contract code, creating a condition where the owner can manipulate token balances in ways that violate the fundamental principles of blockchain tokenomics. The flaw allows for arbitrary balance manipulation through a mathematical overflow condition that occurs when the contract attempts to increment token values beyond their maximum representable limits, effectively enabling the contract owner to set any user's balance to an arbitrary value.
The technical implementation of this vulnerability manifests through improper handling of unsigned integer arithmetic within the smart contract's mintToken function. When the contract attempts to increase a user's token balance through minting operations, the integer overflow occurs at the boundary of the maximum value that can be represented by the data type used for balance tracking. This condition creates a scenario where the mathematical operation wraps around to zero or negative values, allowing the contract owner to bypass normal balance increment logic and directly assign any desired balance value to target accounts. 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 that can be represented by the data type.
The operational impact of this vulnerability extends far beyond simple balance manipulation, creating significant risks for token holders and the overall integrity of the blockchain ecosystem. The contract owner can exploit this flaw to inflate balances of specific users, potentially enabling unauthorized access to funds or creating artificial token distributions that undermine the token's economic model. This capability directly violates the principle of immutability that blockchain systems rely upon, as it allows for arbitrary modifications to the token distribution that cannot be reverted through normal transaction processes. The vulnerability also creates potential for financial loss, as it enables the owner to manipulate token holdings in ways that could disrupt market dynamics or enable fraudulent activities within the token ecosystem.
Mitigation strategies for this vulnerability require immediate code remediation through proper integer overflow protection mechanisms. The smart contract implementation must incorporate bounds checking and explicit overflow detection before any arithmetic operations that could potentially exceed maximum representable values. Developers should utilize established safe math libraries or implement comprehensive validation routines that prevent overflow conditions from occurring. Additionally, the contract owner should consider implementing access control measures that limit the mintToken function to specific authorized entities and establish proper auditing procedures to monitor balance changes. This vulnerability demonstrates the critical importance of thorough smart contract auditing and adherence to secure coding practices, as outlined in the ATT&CK framework for smart contract security. The remediation process should include comprehensive testing of edge cases and validation of all arithmetic operations to ensure that the mathematical integrity of the token system remains intact throughout all operational scenarios.