CVE-2018-13622 in ObjectToken
Summary
by MITRE
The mintToken function of a smart contract implementation for ObjectToken (OBJ), 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 • 02/28/2020
The CVE-2018-13622 vulnerability represents a critical integer overflow flaw within the mintToken function of the ObjectToken (OBJ) smart contract deployed on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operations that fail to account for the maximum limits of integer data types, creating a scenario where an attacker can manipulate token balances through malicious contract interactions. The flaw specifically affects the contract's ability to handle large numerical values during token minting operations, allowing for unexpected behavior that can be exploited for financial gain.
The technical implementation of this vulnerability manifests when the mintToken function processes user inputs without proper overflow checks, particularly when dealing with balance calculations and token distribution. The integer overflow occurs because the contract's code does not validate that the resulting token balance would exceed the maximum value that can be stored in the designated data type. This allows an attacker with owner privileges to manipulate the mintToken function in such a way that arbitrary user balances can be set to any desired value, including potentially unlimited amounts. The vulnerability is classified under CWE-190 as an integer overflow or wraparound, specifically occurring during arithmetic operations where the result exceeds the maximum value representable by the data type.
The operational impact of this vulnerability extends beyond simple balance manipulation, as it fundamentally compromises the integrity of the token economy and can lead to significant financial losses for users and the project itself. An attacker with owner access can create unlimited tokens, manipulate user balances to zero, or inflate balances to arbitrary levels, effectively undermining the token's scarcity and value proposition. This type of vulnerability directly impacts the security posture of the Ethereum ecosystem by demonstrating how poorly implemented arithmetic operations can create persistent weaknesses that affect token distribution and user trust. The vulnerability also aligns with ATT&CK technique T1059.001 for operating system command and script injection, as the malicious code execution occurs within the smart contract environment through legitimate function calls that exploit the underlying integer overflow.
Mitigation strategies for CVE-2018-13622 require immediate implementation of proper input validation and integer overflow protection mechanisms within the smart contract code. Developers should implement explicit checks to ensure that arithmetic operations do not exceed the maximum values of their data types, utilizing safe math libraries or manual overflow detection before performing balance calculations. The contract should validate all inputs to the mintToken function and implement proper bounds checking to prevent the overflow condition from occurring. Additionally, regular security audits and formal verification of smart contract code should be conducted to identify similar vulnerabilities before deployment. The fix should also include comprehensive logging and monitoring of token minting operations to detect anomalous behavior that might indicate exploitation attempts. Organizations should also consider implementing multi-signature ownership controls and time locks for critical contract functions to reduce the risk of unauthorized exploitation, as the vulnerability requires owner privileges to exploit effectively but can cause widespread damage once activated.