CVE-2018-13591 in KAPcoin
Summary
by MITRE
The mintToken function of a smart contract implementation for KAPcoin, 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-2018-13591 represents a critical integer overflow flaw within the mintToken function of the KAPcoin Ethereum token smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's codebase, creating a fundamental security weakness that directly impacts the token's integrity and user funds. The flaw specifically manifests when the mintToken function processes token minting operations, allowing unauthorized manipulation of user balances through controlled arithmetic operations that exceed the maximum value representable by the underlying data types.
The technical exploitation of this vulnerability occurs through the manipulation of integer variables within the smart contract's mintToken function, where the contract fails to properly validate or constrain the values being processed during token creation. When the owner invokes this function with carefully crafted parameters, the integer overflow condition is triggered, enabling the manipulation of user account balances to arbitrary values. This represents a classic example of CWE-190 Integer Overflow or Wraparound, where the contract's arithmetic operations exceed the maximum value that can be stored in the allocated data type, causing unexpected behavior and potential fund manipulation.
The operational impact of this vulnerability extends beyond simple balance manipulation, as it fundamentally compromises the trust model of the KAPcoin token ecosystem. An attacker with access to the contract owner privileges can effectively create unlimited tokens for themselves or manipulate other users' balances, potentially leading to significant financial losses for token holders. The vulnerability affects the core functionality of the token by allowing unauthorized minting of tokens beyond the intended supply limits, creating an inflationary effect that undermines the token's value and security. This flaw also exposes the contract to potential denial of service scenarios where malicious actors could manipulate balances to prevent legitimate transactions.
Mitigation strategies for this vulnerability require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The recommended approach involves adding comprehensive input validation checks before any arithmetic operations, implementing safe math libraries that prevent overflow conditions, and ensuring all integer operations are bounded by appropriate constraints. Organizations should also consider implementing proper access control measures and regular smart contract audits to identify similar vulnerabilities. The remediation process should include code review to ensure all arithmetic operations utilize safe math functions that detect and prevent overflow conditions, as well as implementing proper testing procedures that include edge case scenarios for integer operations. This vulnerability aligns with ATT&CK technique T1548.001 for privilege escalation and T1499.004 for data manipulation, representing a critical security gap that requires immediate attention to maintain the integrity of the Ethereum token ecosystem.