CVE-2018-13092 in Reimburse Token
Summary
by MITRE
The mintToken function of a smart contract implementation for Reimburse Token (REIM), 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 • 02/24/2020
The CVE-2018-13092 vulnerability resides within the Reimburse Token (REIM) smart contract implementation on the Ethereum blockchain, representing a critical integer overflow flaw that fundamentally compromises the contract's integrity and security model. This vulnerability specifically affects the mintToken function, which serves as a mechanism for creating new tokens and allocating them to user addresses. The flaw arises from inadequate input validation and overflow protection mechanisms within the smart contract's code, allowing an attacker with owner privileges to manipulate token balances in ways that violate the fundamental principles of blockchain tokenomics.
The technical implementation of this vulnerability stems from the absence of proper boundary checks when handling integer arithmetic operations within the mintToken function. When the contract processes token minting operations, it fails to validate that the resulting balance values remain within acceptable numerical limits for the Ethereum blockchain's uint256 data type. This oversight creates an environment where an attacker can craft malicious inputs that cause integer overflow conditions, effectively manipulating the token supply and user balances. The vulnerability operates at the core level of the contract's mathematical operations, where standard overflow protections are either absent or improperly implemented, allowing for arbitrary balance manipulation.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial losses and systemic risks within the token ecosystem. An attacker with owner access can exploit this flaw to inflate user balances to arbitrary values, potentially creating unlimited token supply or causing other users to have negative balances that could be exploited for further attacks. The vulnerability represents a direct violation of the principle of least privilege and undermines the trust model that blockchain systems rely upon for secure asset management. This flaw particularly affects the token's governance structure since it allows for unauthorized balance modifications that could be used to manipulate token distribution or create artificial market conditions.
Security professionals should recognize this vulnerability as a classic example of CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic operations exceed the maximum representable value for the data type. The vulnerability also aligns with ATT&CK technique T1548.005, Abuse of Cloud Platform Credentials, as it represents an abuse of contract ownership privileges to manipulate system state. Mitigation strategies must include immediate code review and patching of the mintToken function to implement proper overflow protection mechanisms such as require statements that validate input parameters against maximum value limits. Additionally, comprehensive testing procedures should be established to validate all arithmetic operations within smart contracts, and the contract should be audited for similar vulnerabilities that could exist in other functions. The remediation process must also include a thorough review of the contract's access control mechanisms to ensure that only authorized entities can perform sensitive operations like token minting, and that all modifications to user balances are properly logged and auditable.