CVE-2018-10468 in Useless Ethereum Token
Summary
by MITRE
The transferFrom function of a smart contract implementation for Useless Ethereum Token (UET), an Ethereum ERC20 token, allows attackers to steal assets (e.g., transfer all victims' balances into their account) because certain computations involving _value are incorrect, as exploited in the wild starting in December 2017, aka the "transferFlaw" issue.
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Analysis
by VulDB Data Team • 07/05/2024
The CVE-2018-10468 vulnerability represents a critical flaw in the Useless Ethereum Token (UET) smart contract implementation that fundamentally compromised the security of the ERC20 token standard on the Ethereum blockchain. This vulnerability emerged as a sophisticated attack vector that exploited mathematical computations within the transferFrom function, enabling malicious actors to execute unauthorized transfers of all victim balances into their own accounts. The flaw was particularly dangerous because it operated at the core of token transfer functionality, making it a prime target for exploitation in the rapidly evolving decentralized finance ecosystem that was gaining momentum in late 2017.
The technical root cause of this vulnerability lies in improper handling of arithmetic operations within the smart contract's transferFrom function, specifically involving the _value parameter that governs token transfers between accounts. The implementation contained a critical mathematical error that allowed attackers to manipulate the transfer logic through carefully crafted transaction inputs. This flaw essentially created a condition where the contract's internal state management became vulnerable to manipulation, enabling attackers to bypass normal access controls and transfer all available token balances from any account without proper authorization. The vulnerability falls under CWE-191, Integer Underflow/Overflow, and more specifically aligns with CWE-682, Incorrect Arithmetic, as the flaw stems from improper mathematical computations that result in unexpected behavior within the contract execution environment.
The operational impact of this vulnerability was severe and immediate, as evidenced by the exploitation that occurred in December 2017, making it one of the early and notable examples of smart contract attacks that demonstrated the real-world consequences of such flaws. The attack vector allowed perpetrators to systematically drain all token balances from affected accounts, effectively creating a mechanism for large-scale theft of digital assets. The vulnerability's exploitation was particularly effective because it targeted the fundamental transfer mechanism that every ERC20 token relies upon, making it a critical weakness that could be leveraged across multiple token implementations if similar coding patterns existed. This incident highlighted the importance of rigorous code review and formal verification processes in smart contract development, as the flaw was not just a theoretical concern but a practical threat that caused actual financial losses.
The attack pattern associated with CVE-2018-10468 aligns with several tactics described in the MITRE ATT&CK framework for blockchain environments, particularly focusing on privilege escalation and resource consumption attacks. The vulnerability enabled attackers to perform unauthorized access to token balances, representing a form of account takeover that is particularly devastating in decentralized systems where traditional security controls may not apply. Security researchers and blockchain analysts noted that this flaw demonstrated how seemingly minor arithmetic errors in smart contract code could have catastrophic consequences for asset security, leading to increased awareness of the need for comprehensive security testing and formal verification of blockchain-based applications. The incident contributed significantly to the broader understanding of smart contract security vulnerabilities and influenced subsequent development practices in the Ethereum ecosystem, emphasizing the need for robust mathematical validation in all contract operations.