CVE-2018-13072 in Coffeecoin
Summary
by MITRE
The mintToken function of a smart contract implementation for Coffeecoin (COFFEE), 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 • 02/24/2020
The CVE-2018-13072 vulnerability resides within the mintToken function of Coffeecoin's smart contract implementation on the Ethereum blockchain, representing a critical integer overflow flaw that fundamentally compromises the contract's integrity and financial security. This vulnerability specifically affects the token's supply management mechanism where the mintToken function fails to properly validate integer inputs, creating an exploitable condition that allows malicious actors to manipulate token balances. The flaw occurs when the contract attempts to increment token balances without proper overflow checking, enabling attackers to manipulate the arithmetic operations through carefully crafted inputs that cause the integer values to wrap around and produce unintended results.
The technical nature of this vulnerability aligns with CWE-190, which categorizes integer overflow conditions that can lead to unexpected behavior in software systems. In the context of Ethereum smart contracts, this represents a classic example of insufficient input validation and arithmetic boundary checking that violates fundamental security principles. The vulnerability operates by exploiting the mathematical properties of fixed-width integer representations in the Ethereum virtual machine, where operations that exceed the maximum value for a given data type cause the value to wrap around to zero or negative values, creating unpredictable states within the contract's balance tracking mechanism. This particular implementation fails to implement proper overflow detection mechanisms that would normally be enforced by modern Solidity compiler versions or require explicit overflow protection through SafeMath libraries.
The operational impact of this vulnerability extends beyond simple balance manipulation, as it fundamentally undermines the trust model that underpins cryptocurrency systems. An attacker with access to the contract owner privileges can arbitrarily set any user's balance to any value, potentially creating infinite token supply conditions or setting balances to zero, thereby enabling unauthorized wealth redistribution or complete contract compromise. This vulnerability directly impacts the contract's core functionality and financial integrity, allowing for potential theft of funds, manipulation of token distributions, and complete subversion of the token's economic model. The consequences are particularly severe in decentralized finance environments where such vulnerabilities can be exploited to drain contract reserves or manipulate token prices through artificial balance manipulation.
Mitigation strategies for CVE-2018-13072 require immediate implementation of proper integer overflow protection mechanisms within the smart contract code. The recommended approach involves implementing SafeMath libraries or enabling compiler overflow checks through pragma directives such as pragma solidity ^0.8.0, which automatically includes overflow protection for arithmetic operations. Additionally, all contract functions that manipulate token balances should include comprehensive input validation and boundary checking to prevent invalid values from being processed. The fix should also include proper access control mechanisms to ensure that only authorized entities can execute mintToken operations, combined with thorough code auditing and formal verification processes to identify similar vulnerabilities across the entire smart contract ecosystem. Organizations should also implement regular security assessments and consider using automated tools to detect potential integer overflow conditions in their smart contract implementations, aligning with ATT&CK technique T1587 for adversary infrastructure and T1078 for valid accounts to ensure proper access control measures are in place to prevent unauthorized exploitation of such vulnerabilities.