CVE-2018-13705 in PMHToken
Summary
by MITRE
The mintToken function of a smart contract implementation for PMHToken, 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 described in CVE-2018-13705 represents a critical integer overflow flaw within the mintToken function of a PMHToken smart contract deployed on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic overflow handling within the contract's implementation, creating a fundamental security weakness that directly impacts the token's integrity and user fund safety. The flaw allows the contract owner to manipulate user balances arbitrarily, effectively enabling unauthorized fund manipulation and potential theft of token holdings. Such vulnerabilities are particularly dangerous in decentralized finance applications where user trust and asset security are paramount.
The technical implementation of this vulnerability manifests through improper handling of integer arithmetic operations within the mintToken function. When the contract attempts to increment user balances or perform other arithmetic operations, the lack of overflow checks allows values to wrap around to unexpected states. This behavior occurs because the smart contract does not properly validate that arithmetic operations remain within acceptable integer bounds before performing calculations. The vulnerability specifically affects the token's minting mechanism, where the owner can invoke the function to create new tokens and simultaneously manipulate existing user balances. According to CWE-190, this represents an integer overflow condition that can be exploited to manipulate program state and data integrity. The flaw aligns with ATT&CK technique T1499.001 which involves data manipulation through code injection and privilege escalation mechanisms.
The operational impact of this vulnerability extends beyond simple balance manipulation to encompass potential financial loss, contract integrity compromise, and trust erosion within the token ecosystem. An attacker with owner privileges can exploit this vulnerability to inflate their own holdings while simultaneously reducing other users' balances to zero or negative values. This creates a scenario where the contract's economic model becomes fundamentally compromised, as the owner can effectively control the distribution of all token holdings. The vulnerability also poses risks to downstream applications that depend on accurate token balances, potentially affecting exchanges, wallets, and other smart contracts that interact with the affected token. The exploitability of this vulnerability is particularly concerning because it requires minimal technical expertise to execute and can cause irreversible damage to user assets.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements within smart contract development practices. The primary fix involves implementing proper integer overflow checks using require statements or SafeMath libraries that prevent arithmetic operations from exceeding maximum integer values. Contract developers should also implement comprehensive input validation for all user-supplied parameters and ensure that owner privileges are properly constrained and monitored. Additionally, regular security audits and formal verification processes should be integrated into the development lifecycle to identify similar vulnerabilities before deployment. The implementation of access control mechanisms and multi-signature wallets for contract ownership can further reduce the risk of unauthorized exploitation. Organizations should also consider implementing automated monitoring systems to detect unusual balance changes or minting activities that may indicate exploitation attempts. These measures align with security frameworks such as the OWASP Smart Contract Security Verification Standard and emphasize the importance of defensive programming practices in blockchain development environments.