CVE-2018-13202 in MyBO
Summary
by MITRE
The sell function of a smart contract implementation for MyBO, 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-2018-13202 represents a critical integer overflow flaw within the sell function of MyBO token smart contract implementations on the Ethereum blockchain. This vulnerability stems from improper input validation and arithmetic operation handling within the contract's code, specifically when processing token sell transactions. The flaw manifests when the product of amount and sellPrice calculations results in zero, which fundamentally undermines the contract's ability to accurately process token sales and maintain proper asset accounting for sellers.
The technical nature of this vulnerability aligns with CWE-191, which describes integer underflow/overflow conditions, and CWE-682, which covers incorrect arithmetic operations. The integer overflow occurs because the smart contract fails to properly validate or sanitize the multiplication operation between the token amount being sold and the current sell price. When this multiplication results in zero due to overflow conditions or improper handling of large integer values, the contract's logic incorrectly processes the transaction, leading to asset depletion for token sellers. This vulnerability operates at the core of blockchain smart contract security principles where mathematical operations must be rigorously validated to prevent unintended consequences.
The operational impact of this vulnerability extends beyond simple financial loss, as it fundamentally compromises the integrity of the token economy and user trust within the MyBO ecosystem. Sellers who attempt to liquidate their tokens face the risk of losing their entire holdings or experiencing significant asset reduction, as the zero result from the multiplication operation effectively nullifies their transaction. This flaw creates a cascading effect that can destabilize the token's market value and liquidity, particularly if multiple users encounter this issue simultaneously. The vulnerability also exposes the broader smart contract ecosystem to potential exploitation through similar arithmetic overflow patterns that could affect other token implementations.
Mitigation strategies for CVE-2018-13202 require comprehensive code review and implementation of robust input validation mechanisms within the smart contract's sell function. The solution involves incorporating explicit overflow checks using libraries such as OpenZeppelin's SafeMath or similar arithmetic libraries that prevent overflow conditions through built-in validation. Additionally, developers should implement proper boundary checks for all arithmetic operations, particularly multiplication functions, to ensure that intermediate results remain within acceptable ranges. The fix must also include thorough testing with edge cases, including maximum integer values and zero values, to verify that the contract handles all possible input scenarios correctly. Organizations should also consider implementing formal verification techniques and continuous security monitoring to detect similar vulnerabilities in other smart contract implementations, aligning with ATT&CK technique T1587 for adversary infrastructure development and T1078 for valid accounts.