CVE-2018-13207 in PornCoin
Summary
by MITRE
The sell function of a smart contract implementation for PornCoin (PRNC), an Ethereum token, has an integer overflow in which "amount * sellPrice" can be zero, consequently reducing a seller's assets.
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Analysis
by VulDB Data Team • 02/25/2020
The vulnerability identified in CVE-2018-13207 affects the PornCoin (PRNC) smart contract implementation on the Ethereum blockchain, specifically targeting the sell function within the token's smart contract code. This represents a critical security flaw that directly impacts the financial integrity of users who hold and trade this cryptocurrency. The issue stems from improper handling of arithmetic operations within the smart contract's logic, creating a scenario where mathematical calculations can produce unexpected results due to inadequate input validation and overflow protection mechanisms.
The technical flaw manifests as an integer overflow condition within the sell function where the calculation "amount * sellPrice" can result in zero values under certain circumstances. This occurs because the smart contract fails to properly validate the input parameters before performing multiplication operations, allowing malicious actors or simply users with specific token amounts to exploit this weakness. When the multiplication operation produces a zero result, it effectively nullifies the intended transaction value, causing sellers to lose assets that should have been transferred to them during the selling process. The vulnerability falls under the CWE-191 category of integer underflow/overflow, specifically manifesting as an integer overflow condition that leads to unexpected behavior in the contract's financial calculations.
From an operational perspective, this vulnerability creates significant financial risks for users of the PornCoin token, as it directly impacts their ability to realize value from selling their holdings. The zero result from the multiplication operation means that sellers receive no compensation for their tokens, effectively draining their assets without proper transaction processing. This type of vulnerability can be exploited repeatedly, potentially leading to substantial financial losses for affected users and undermining confidence in the token's legitimacy. The attack surface is particularly concerning because it operates within the decentralized environment of blockchain technology where transactions are irreversible and smart contract logic governs all financial operations without traditional oversight mechanisms.
The mitigation strategies for this vulnerability require immediate code modifications to implement proper integer overflow protection mechanisms and input validation. Smart contract developers should employ explicit bounds checking and use libraries such as OpenZeppelin's SafeMath to prevent arithmetic operations from producing unexpected results. Additionally, comprehensive testing including edge case scenarios and formal verification methods should be implemented to identify similar vulnerabilities before deployment. The ATT&CK framework categorizes this type of vulnerability under the T1210 technique of Exploitation of Remote Services, as it represents an exploitable weakness in a deployed smart contract system. Organizations should also consider implementing monitoring solutions to detect unusual transaction patterns that might indicate exploitation attempts, while adhering to industry best practices for smart contract security as outlined in the Ethereum Smart Contract Security Best Practices guidelines and the OWASP Smart Contract Security Verification Standard.