CVE-2018-13549 in NeuroToken
Summary
by MITRE
The mintToken function of a smart contract implementation for NeuroToken, 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.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 02/27/2020
The vulnerability identified in CVE-2018-13549 represents a critical integer overflow flaw within the mintToken function of the NeuroToken smart contract implementation on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic handling within the contract's code, specifically affecting the token's issuance mechanism. The flaw allows the contract owner to manipulate user balances by setting them to arbitrary values, fundamentally compromising the token's integrity and the underlying blockchain's trust model. The vulnerability is classified as a CWE-191 Integer Underflow/Overflow, which falls under the broader category of CWE-682 Incorrect Calculation, making it a direct threat to the contract's financial security and user asset protection.
The technical exploitation of this vulnerability occurs through the mintToken function's failure to properly validate or constrain integer values during balance updates. When the owner invokes this function, the contract performs arithmetic operations without adequate overflow checks, enabling the manipulation of user account balances to predetermined values. This flaw essentially creates a backdoor for the contract owner to arbitrarily increase or decrease any user's token balance, potentially leading to massive financial losses for token holders and undermining the decentralized trust that blockchain technology relies upon. The vulnerability is particularly dangerous because it operates at the core of the token's distribution mechanism, allowing for unauthorized wealth transfer and potential exploitation of the entire token economy.
The operational impact of CVE-2018-13549 extends beyond immediate financial loss to encompass broader security implications for the entire Ethereum ecosystem. This vulnerability demonstrates how a single flaw in smart contract code can compromise the fundamental principles of blockchain security, potentially affecting user confidence in token-based systems and creating precedents for similar attacks on other smart contracts. The vulnerability's impact is amplified by the fact that it allows for arbitrary balance manipulation, which could enable the creation of unlimited tokens, manipulation of trading prices, or even the complete theft of user funds. From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.001 Command and Scripting Interpreter and T1496 Resource Hijacking, as it enables unauthorized resource allocation and manipulation of contract state.
Mitigation strategies for this vulnerability require immediate code remediation through proper integer overflow protection mechanisms, including the implementation of bounded arithmetic checks and input validation within the mintToken function. The recommended approach involves using safe arithmetic libraries or implementing explicit overflow detection before any balance modifications occur, ensuring that all integer operations maintain valid ranges and prevent unauthorized value manipulation. Additionally, comprehensive code audits should be conducted to identify similar vulnerabilities in other contract functions, as integer overflows often occur in multiple locations within complex smart contracts. The fix should also include proper access control mechanisms to ensure that only authorized entities can perform token minting operations, and that all balance modifications are logged and auditable to detect any unauthorized manipulations. This vulnerability underscores the critical importance of thorough security testing and formal verification processes for smart contracts before deployment, as well as the necessity of implementing robust monitoring systems to detect anomalous contract behavior.