CVE-2018-13198 in STeX Exchange ICO
Summary
by MITRE
The sell function of a smart contract implementation for STeX Exchange ICO (STE), 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-2018-13198 represents a critical integer overflow flaw within the sell function of the STeX Exchange ICO (STE) smart contract deployed on the Ethereum blockchain. This vulnerability stems from inadequate input validation and arithmetic operation handling within the contract's code implementation. The specific issue occurs when the contract attempts to calculate "amount * sellPrice" during the token selling process, where the multiplication operation can result in an integer overflow or underflow condition. When this arithmetic operation produces a zero value, it fundamentally undermines the token holder's ability to properly execute sell transactions and results in the unauthorized reduction of their asset holdings.
The technical nature of this vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions in software implementations. In the context of smart contracts, this flaw represents a severe security weakness that directly impacts the contract's integrity and the users' ability to control their digital assets. The vulnerability manifests when the multiplication of the token amount being sold and the current sell price results in an arithmetic overflow that wraps around to zero or produces an invalid value. This condition effectively allows malicious actors to manipulate the sell function in such a way that sellers lose access to their intended token quantities, creating a scenario where asset values are silently diminished without proper authorization.
The operational impact of this vulnerability extends beyond simple financial loss, as it fundamentally compromises the trust and reliability of the STeX Exchange platform. Token holders who attempt to sell their STE tokens may find that their transactions are processed incorrectly, resulting in partial or complete loss of their holdings. This vulnerability creates a dangerous precedent for investors and users who rely on smart contracts for secure asset management, as it demonstrates that even well-intentioned token sales can contain critical flaws that directly impact user assets. The consequences are particularly severe in decentralized exchanges where users have limited recourse when such vulnerabilities are exploited.
Mitigation strategies for this vulnerability require immediate code review and patching of the affected smart contract implementation. The fix must involve implementing proper integer overflow protection mechanisms such as using safe math libraries, adding explicit bounds checking before arithmetic operations, and ensuring that all multiplication operations are validated against potential overflow conditions. Additionally, the contract should implement comprehensive input validation to prevent invalid transaction parameters from being processed. Organizations should also consider implementing multi-signature transaction requirements for major operations and establishing formal auditing processes to identify and remediate similar vulnerabilities before deployment. The ATT&CK framework's T1059.001 technique of command and scripting interpreter could be relevant in analyzing how such vulnerabilities might be exploited through automated transaction manipulation, emphasizing the need for robust contract validation mechanisms.