CVE-2018-13465 in PaulyCoin
Summary
by MITRE
The mintToken function of a smart contract implementation for PaulyCoin, 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 • 02/26/2020
The vulnerability identified as CVE-2018-13465 resides within the mintToken function of PaulyCoin, an Ethereum-based smart contract token implementation. This flaw represents a critical integer overflow condition that fundamentally compromises the contract's integrity and security model. The vulnerability allows the contract owner to manipulate user balances arbitrarily, creating a severe disruption to the token's economic system and potentially enabling unauthorized value transfers. Such a flaw directly violates fundamental principles of blockchain security where trustless and deterministic execution should be guaranteed. The integer overflow occurs during the minting process when calculations exceed the maximum representable value for the data type used, causing unexpected behavior in the balance accounting system.
The technical implementation of this vulnerability stems from inadequate input validation and arithmetic overflow handling within the smart contract code. When the mintToken function processes token creation requests, it performs calculations that do not properly check for overflow conditions before assigning new balances to user accounts. This creates a scenario where an attacker with owner privileges can manipulate the underlying integer values to achieve arbitrary balance assignments. The vulnerability maps directly to CWE-190, which describes integer overflow and underflow conditions, and specifically aligns with CWE-682, concerning computations that yield incorrect results due to arithmetic operations. The flaw demonstrates poor defensive programming practices where the contract fails to implement proper boundary checks and overflow protection mechanisms that are standard in secure smart contract development.
Operationally, this vulnerability presents significant risks to the token ecosystem and its users. The contract owner can effectively create unlimited tokens for themselves while simultaneously manipulating other users' balances, potentially leading to total loss of funds for affected parties. The impact extends beyond individual user accounts to potentially destabilize the entire token economy, as the value distribution becomes unpredictable and controllable by a single privileged entity. This vulnerability enables several attack vectors including account manipulation, unauthorized token creation, and potential theft of funds from other users. From an attacker's perspective, this represents a high-value exploit opportunity that can be leveraged for financial gain without requiring complex technical skills or external resources. The vulnerability also creates trust issues within the token community, as users cannot rely on the integrity of their account balances or the fairness of the token distribution mechanism.
Mitigation strategies for CVE-2018-13465 must address both immediate remediation and long-term security improvements. The primary fix involves implementing comprehensive overflow protection mechanisms using safe math libraries such as OpenZeppelin's SafeMath or similar implementations that automatically detect and prevent arithmetic overflow conditions. Smart contract developers should also implement proper access control measures and conduct thorough code reviews to identify similar vulnerabilities across all arithmetic operations. The contract owner must disable or remove the vulnerable mintToken function until proper safeguards are implemented. Additionally, regular security audits and formal verification techniques should be employed to ensure that similar vulnerabilities do not exist in other contract functions. Organizations implementing Ethereum-based tokens should establish robust development practices that adhere to industry standards such as those recommended by the Ethereum Foundation and security frameworks like the OWASP Smart Contract Security Verification Standard. The vulnerability also highlights the importance of continuous monitoring and post-deployment security measures to detect and respond to potential exploits in live smart contract environments.