CVE-2018-13690 in Instacocoa
Summary
by MITRE
The mintToken function of a smart contract implementation for Instacocoa, 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 vulnerability identified as CVE-2018-13690 represents a critical integer overflow flaw within the mintToken function of Instacocoa's Ethereum smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic handling within the token contract's code, creating a scenario where the contract owner can manipulate user balances without proper authorization. The flaw directly impacts the fundamental integrity of the token system by allowing unauthorized balance manipulation that violates the core principles of blockchain-based asset management.
The technical execution of this vulnerability occurs through the mintToken function's improper handling of integer arithmetic operations. When the contract attempts to increment user balances through minting operations, the lack of overflow checks allows for wrapping behavior where large integer values exceed the maximum representable limit and wrap around to zero or negative values. This creates a condition where the contract owner can calculate specific parameters to force the balance update to any desired value, effectively bypassing normal token minting restrictions and user account management protocols. The vulnerability maps directly to CWE-190, which specifically addresses integer overflow conditions that can lead to unpredictable behavior and security breaches in software implementations.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial loss and systemic trust erosion within the Instacocoa token ecosystem. An attacker with owner privileges can artificially inflate user balances to arbitrary amounts, potentially leading to massive dilution of token value or unauthorized access to funds. The vulnerability also creates opportunities for further exploitation, as the compromised contract state can be leveraged to execute additional malicious operations within the smart contract environment. This type of vulnerability aligns with ATT&CK technique T1059.006 for smart contract manipulation and represents a significant vector for financial theft through unauthorized minting operations.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive input validation and integer overflow protection mechanisms within the smart contract code. The mintToken function must incorporate proper boundary checks using techniques such as SafeMath libraries or explicit overflow detection before performing arithmetic operations. Contract owners should implement multi-signature authorization requirements for minting operations to prevent single points of failure and reduce the attack surface. Additionally, regular smart contract audits and formal verification processes should be established to identify similar vulnerabilities before deployment. The remediation process must include thorough testing of edge cases and comprehensive validation of all arithmetic operations within token contracts to ensure that integer overflow conditions cannot be exploited by malicious actors.