CVE-2018-13555 in JaxBox
Summary
by MITRE
The mintToken function of a smart contract implementation for JaxBox, 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-2018-13555 represents a critical integer overflow flaw within the mintToken function of the JaxBox Ethereum token smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's codebase, creating a fundamental security weakness that directly impacts the token's integrity and user fund safety. The flaw exists at the core level of the contract's balance management system, where the mintToken function fails to properly validate or constrain the values being processed during token creation operations.
The technical exploitation of this vulnerability occurs when the contract owner invokes the mintToken function with maliciously crafted parameters that exceed the maximum value limits of the integer data types used in the smart contract. This overflow condition allows the attacker to manipulate the balance of any user account within the token system, effectively enabling arbitrary balance manipulation and potential theft of funds. The vulnerability specifically relates to the lack of proper overflow checking mechanisms in the contract's arithmetic operations, which is a well-documented weakness categorized under CWE-190 as Integer Overflow or Wraparound. The implementation fails to adhere to proper secure coding practices that should prevent such arithmetic overflows from occurring during token minting operations.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential systemic risks within the JaxBox token ecosystem. An attacker with contract ownership privileges can exploit this flaw to inflate user balances to arbitrary amounts, potentially leading to unauthorized token distribution and financial loss for legitimate token holders. The vulnerability creates a persistent risk that remains active until the underlying smart contract code is patched and redeployed, making it particularly dangerous for users who may not be aware of the compromised state of their tokens. This type of vulnerability falls under the ATT&CK framework category of Privilege Escalation through Smart Contract Manipulation, where an attacker leverages existing privileges to gain unauthorized control over system resources.
Mitigation strategies for CVE-2018-13555 require immediate patching of the smart contract implementation to include proper integer overflow protections and input validation mechanisms. The recommended approach involves implementing comprehensive range checking and using secure arithmetic operations that prevent overflow conditions from occurring during token creation processes. Additionally, contract owners should consider implementing multi-signature ownership controls and regular security audits to prevent unauthorized exploitation of such vulnerabilities. The fix should incorporate modern secure coding practices including the use of libraries like OpenZeppelin's SafeMath to prevent arithmetic overflows, and thorough testing of all contract functions to ensure proper handling of edge cases and boundary conditions. Organizations should also establish robust monitoring systems to detect anomalous balance changes that might indicate exploitation attempts of similar vulnerabilities.