CVE-2018-13765 in LandCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for LandCoin, 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 vulnerability identified in CVE-2018-13765 represents a critical integer overflow flaw within the mintToken function of the LandCoin Ethereum smart contract implementation. This vulnerability stems from inadequate input validation and arithmetic operation handling within the smart contract's codebase, specifically affecting the token minting mechanism that allows contract owners to create new tokens. The flaw exists at the core of the contract's balance management system where unsigned integer arithmetic operations fail to properly check for overflow conditions before executing mathematical calculations. When the mintToken function processes token creation requests, it performs arithmetic operations on token balances without sufficient boundary checks, creating a scenario where malicious actors can manipulate the underlying integer values to achieve unintended outcomes.
The technical exploitation of this vulnerability occurs through the manipulation of the token minting process where the contract owner can leverage the integer overflow to set arbitrary user balances to any desired value. This flaw operates under CWE-191 - Integer Underflow/Overflow, which specifically addresses issues where integer arithmetic operations produce results that exceed the maximum or minimum values representable by the data type. The vulnerability allows for the creation of tokens with balances that exceed the maximum value that can be represented by the unsigned integer type, effectively causing the integer to wrap around to a much smaller value or zero. This behavior can be systematically exploited to manipulate token distributions and potentially drain contract resources or create artificial token supply inflation.
The operational impact of this vulnerability extends beyond simple balance manipulation and presents significant risks to the integrity of the LandCoin token economy. Attackers can exploit this flaw to generate unlimited tokens for themselves or other users, potentially leading to complete economic disruption of the token system. The vulnerability enables contract owners to bypass normal token distribution mechanisms and directly manipulate account balances, creating a scenario where unauthorized parties can accumulate excessive token holdings. This type of vulnerability directly impacts the security model of the Ethereum token ecosystem and can result in financial losses for token holders and the broader community. The vulnerability also creates potential for denial of service attacks where malicious actors can manipulate token balances to prevent legitimate transactions or create system instability. According to ATT&CK framework, this vulnerability maps to T1068 - Exploitation for Privilege Escalation and T1499 - Endpoint Termination, as it allows for unauthorized privilege escalation within the token contract and can potentially lead to complete system compromise.
Mitigation strategies for CVE-2018-13765 require immediate code review and implementation of proper integer overflow protections within the smart contract. The recommended approach involves implementing explicit boundary checks before any arithmetic operations, utilizing safe arithmetic libraries, or employing compiler features that automatically detect and prevent integer overflows. Contract developers should implement require statements to validate input parameters and ensure that balance calculations remain within acceptable ranges. Additionally, the contract should utilize overflow protection mechanisms such as OpenZeppelin's SafeMath library or similar implementations that provide built-in protection against integer overflows. Regular security audits and formal verification processes should be implemented to identify similar vulnerabilities in smart contract code. The vulnerability highlights the importance of adhering to secure coding practices for blockchain applications and demonstrates how seemingly simple arithmetic operations can create critical security flaws when not properly validated. Organizations should also consider implementing access control mechanisms that limit the privileges of contract owners and establish proper governance procedures for token management operations.