CVE-2018-13578 in GalaxyCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for GalaxyCoin, 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-2018-13578 represents a critical integer overflow flaw within the mintToken function of GalaxyCoin's Ethereum smart contract implementation. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types. The flaw allows the contract owner to manipulate token balances through a mathematical overflow condition that occurs when attempting to exceed the maximum value that can be represented by the underlying integer type. The vulnerability is classified under CWE-191 as an integer underflow or overflow, specifically manifesting as an unsigned integer overflow that can be exploited to manipulate contract state. The issue directly violates the fundamental principles of secure smart contract development as outlined in the Ethereum Smart Contract Security Best Practices and Solidity security guidelines.
The technical exploitation of this vulnerability occurs when the mintToken function processes token minting operations without proper bounds checking on the amount parameter. When an attacker or contract owner provides a value that would cause the integer to exceed its maximum representable value, the overflow condition results in an unexpected wraparound behavior. This wraparound can be manipulated to set arbitrary user balances to predetermined values, effectively allowing for unlimited token generation or manipulation of user accounts. The vulnerability is particularly dangerous because it resides in the owner-only function, meaning that only the contract creator or designated owner can exploit it, but the impact is severe enough to compromise the entire token economy. The overflow condition typically occurs in Solidity contracts when arithmetic operations exceed the maximum value of uint256 type, which is 2^256 - 1, and the operation wraps around to zero or a negative value.
The operational impact of this vulnerability extends far beyond simple balance manipulation and can completely undermine the integrity of the GalaxyCoin token ecosystem. An attacker with owner privileges can arbitrarily inflate their own token holdings or manipulate other users' balances to create artificial scarcity or distribute tokens unfairly. This manipulation can lead to market manipulation, loss of user trust, and potentially complete financial losses for token holders. The vulnerability creates a fundamental weakness in the token's supply mechanism, as the owner can effectively bypass all normal token minting controls and create unlimited tokens at will. The impact is particularly severe in decentralized finance applications where such vulnerabilities can be exploited to drain liquidity pools or manipulate token prices. This type of vulnerability also enables potential attacks against smart contract systems that rely on accurate token balances for their operations, including those following the ERC-20 standard and associated security protocols.
Mitigation strategies for CVE-2018-13578 require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The primary solution involves adding explicit bounds checking and overflow protection using Solidity's built-in features such as SafeMath library or explicit overflow checks before arithmetic operations. The contract owner should implement comprehensive input validation that verifies all parameters passed to the mintToken function and ensures that values remain within acceptable ranges. Additionally, the contract should utilize the require statement to validate inputs and prevent execution when overflow conditions would occur. The implementation should follow the principle of least privilege and consider implementing multi-signature ownership controls to prevent single points of failure. Security audits should be conducted to identify similar vulnerabilities in other contract functions, as integer overflows are common across smart contract implementations. Organizations should also consider implementing automated testing frameworks that specifically target integer overflow conditions and ensure that all arithmetic operations in smart contracts include proper overflow protection mechanisms. The vulnerability demonstrates the critical importance of following established security standards and best practices for Ethereum smart contract development, including those recommended by the OpenZeppelin security guidelines and the Ethereum Improvement Proposal standards.