CVE-2018-13562 in BMVCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for BMVCoin, 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-2018-13562 represents a critical integer overflow flaw within the mintToken function of BMVCoin smart contract implementation on the Ethereum blockchain. This vulnerability resides in the core tokenomics mechanism that governs the creation and distribution of BMVCoin tokens, fundamentally compromising the integrity of the token economy. The flaw specifically manifests in the mintToken function where insufficient input validation and overflow protection mechanisms allow malicious actors to manipulate token balances through crafted transaction parameters. The vulnerability enables the contract owner to arbitrarily set any user's token balance to any desired value, effectively undermining the fundamental principles of blockchain token economics and user asset security. This issue directly relates to CWE-190, which categorizes integer overflow conditions as a critical weakness in software systems.
The technical exploitation of this vulnerability occurs when the mintToken function processes token minting operations without proper bounds checking on the balance parameters. In Ethereum smart contracts, integer overflows can occur when arithmetic operations exceed the maximum value that can be stored in a given data type, causing the value to wrap around to zero or negative values. The BMVCoin implementation fails to implement proper overflow protection mechanisms such as SafeMath libraries or explicit boundary checks that are standard practices in secure smart contract development. This allows an attacker with owner privileges to craft transactions that manipulate the internal balance storage of any user account, potentially creating unlimited tokens or setting arbitrary balances that could disrupt the entire token economy.
The operational impact of this vulnerability extends beyond simple balance manipulation to potentially compromise the entire BMVCoin ecosystem. An attacker with owner access could inflate token supplies, create artificial wealth for specific accounts, or even drain legitimate user balances by setting them to zero or negative values. This vulnerability fundamentally undermines trust in the token's value proposition and could lead to market manipulation, loss of user funds, and complete collapse of the token's economic model. The implications are particularly severe because Ethereum smart contracts operate with immutable code, meaning that once deployed with this vulnerability, the flaw persists indefinitely without a complete contract redeployment. The vulnerability also aligns with ATT&CK technique T1548.001, which describes privilege escalation through abuse of administrative access, as the attacker leverages their owner role to execute malicious operations that compromise system integrity.
Mitigation strategies for CVE-2018-13562 require immediate implementation of secure coding practices and comprehensive code review processes for all smart contract deployments. The primary fix involves incorporating proper overflow protection mechanisms such as SafeMath libraries or explicit bounds checking before any arithmetic operations in the mintToken function. Additionally, contract owners should implement multi-signature wallet systems and regular security audits to prevent unauthorized access to privileged functions. The vulnerability highlights the critical importance of following established security frameworks and standards such as those outlined in the Ethereum Smart Contract Security Best Practices documentation. Organizations should also consider implementing automated security testing tools and formal verification methods to identify similar vulnerabilities before deployment. The remediation process must include thorough testing of all contract functions with boundary value analysis and stress testing to ensure that integer operations behave correctly under all conditions.