CVE-2018-12062 in SwftCoin
Summary
by MITRE
The sell function of a smart contract implementation for SwftCoin (SWFTC), a tradable Ethereum ERC20 token, allows a potential trap that could be used to cause financial damage to the seller, because of overflow of the multiplication of its argument amount and a manipulable variable sellPrice, aka the "tradeTrap" issue.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/21/2020
The vulnerability identified as CVE-2018-12062 resides within the sell function of SwftCoin's smart contract implementation, representing a critical flaw that directly impacts the financial security of token holders. This issue manifests through an arithmetic overflow condition that occurs when multiplying the user-specified amount parameter with the manipulable sellPrice variable, creating a scenario where malicious actors can exploit the contract's mathematical operations to cause unintended financial losses for sellers. The vulnerability specifically affects the ERC20 token standard implementation used by SwftCoin, making it susceptible to manipulation through carefully crafted input values that trigger the overflow condition.
The technical flaw stems from the absence of proper overflow protection mechanisms within the smart contract's arithmetic operations, particularly in the sell function's multiplication logic. When a user attempts to sell SWFTC tokens, the contract multiplies the amount being sold with the current sellPrice to determine the value of the transaction. However, without adequate checks for integer overflow conditions, this multiplication operation can produce results that exceed the maximum value that can be stored in the designated data type. This mathematical overflow creates a scenario where the calculated value wraps around to a much smaller number, effectively allowing attackers to manipulate the transaction outcome and potentially drain funds or cause the seller to receive significantly less value than expected. The vulnerability is classified under CWE-191, which specifically addresses integer underflow/overflow issues in software systems.
The operational impact of this vulnerability extends beyond simple financial loss, as it creates a fundamental trust issue within the token ecosystem and demonstrates the critical importance of proper input validation in smart contract development. When a seller attempts to execute a sell transaction, they may unknowingly trigger the overflow condition, causing the contract to calculate incorrect values that can result in substantial financial damage. The "tradeTrap" moniker reflects how this vulnerability can be strategically exploited to trap unsuspecting users into transactions that benefit the attacker while causing financial harm to the victim. This type of vulnerability directly impacts the security model of the entire SwftCoin platform and undermines user confidence in the token's value and transaction integrity. The vulnerability also aligns with ATT&CK technique T1059.001, which involves the manipulation of software to execute malicious code, as the overflow condition creates an unintended execution path that can be exploited by adversaries.
Mitigation strategies for this vulnerability require immediate implementation of proper overflow protection mechanisms within the smart contract's arithmetic operations. Developers must implement explicit checks before any multiplication operations that could potentially overflow, utilizing libraries such as OpenZeppelin's SafeMath or similar mathematical operation protection functions that automatically detect and prevent overflow conditions. Additionally, the sellPrice variable should be properly validated to ensure it cannot be manipulated to values that would cause overflow conditions when multiplied with user-specified amounts. The contract should also implement comprehensive input validation and parameter checking to prevent malicious actors from crafting transactions that exploit the mathematical overflow. Furthermore, regular smart contract audits should be conducted to identify similar vulnerabilities, and developers should follow established security best practices for Ethereum smart contract development as outlined in the Solidity documentation and security guidelines from the Ethereum Foundation. The vulnerability demonstrates the critical need for thorough testing of mathematical operations in smart contracts and the importance of implementing defensive programming practices to prevent such arithmetic overflow conditions from being exploited by malicious actors.