CVE-2018-13769 in JeansToken
Summary
by MITRE
The mintToken function of a smart contract implementation for JeansToken, 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 • 03/03/2020
The CVE-2018-13769 vulnerability represents a critical integer overflow flaw within the mintToken function of the JeansToken Ethereum smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's codebase, creating a significant security risk that directly impacts the token's integrity and user funds. The flaw allows the contract owner to manipulate user balances arbitrarily, fundamentally undermining the trustless nature of blockchain-based token systems. The vulnerability is classified under CWE-191 as an integer underflow or overflow, specifically manifesting as an unsigned integer overflow in the token minting process. This type of vulnerability falls within the ATT&CK framework's software vulnerabilities category, specifically targeting smart contract execution environments where financial assets are at stake.
The technical implementation of this vulnerability occurs when the mintToken function processes token minting operations without proper bounds checking on the amount parameter. In Ethereum smart contracts, integer overflow vulnerabilities typically arise when arithmetic operations exceed the maximum value that can be stored in the designated data type, causing the value to wrap around to zero or negative values. The JeansToken contract's mintToken function fails to validate that the token amount being minted does not exceed the maximum value for the underlying integer type, enabling the contract owner to craft malicious inputs that manipulate the token balance calculation. This flaw is particularly dangerous because it directly affects the core accounting mechanism of the token, allowing the owner to either inflate or deflate user balances at will, potentially leading to unauthorized fund transfers or account manipulation.
The operational impact of CVE-2018-13769 extends beyond simple balance manipulation, creating cascading security risks within the token ecosystem. An attacker with owner privileges can exploit this vulnerability to drain funds from other users by setting their balances to zero or to create unlimited tokens by manipulating the total supply calculations. The vulnerability affects all users of the JeansToken who rely on the contract's integrity for their token holdings, potentially resulting in complete loss of funds for affected parties. The financial implications are severe as users may lose confidence in the token's value and security, leading to market instability and potential regulatory scrutiny. Additionally, the vulnerability demonstrates a fundamental flaw in the contract's access control and input validation mechanisms, exposing the broader Ethereum ecosystem to similar risks when developers fail to implement proper security practices in smart contract development.
Mitigation strategies for CVE-2018-13769 require immediate code-level fixes and comprehensive security audits of the affected smart contract implementation. The primary solution involves implementing proper bounds checking and overflow protection mechanisms using modern Solidity practices such as SafeMath library usage or compiler versions that include built-in overflow checks. Contract developers must ensure that all arithmetic operations within token minting and transfer functions include validation checks to prevent integer overflow conditions. Additionally, regular security audits and formal verification processes should be implemented to identify similar vulnerabilities before deployment. The vulnerability highlights the importance of adhering to security best practices outlined in the Solidity documentation and industry standards for smart contract development. Organizations should also consider implementing multi-signature ownership controls and time locks for critical contract functions to prevent unauthorized exploitation of such vulnerabilities. The remediation process must include thorough testing of edge cases and comprehensive deployment validation to ensure that similar vulnerabilities do not exist in other contract functions or related systems.