An integer overflow in the batchTransfer function of a smart contract implementation for Beauty Ecosystem Coin (BEC), the Ethereum ERC20 token used in the Beauty Chain economic system, allows attackers to accomplish an unauthorized increase of digital assets by providing two _receivers arguments in conjunction with a large _value argument, as exploited in the wild in April 2018, aka the "batchOverflow" issue.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
| Link | Tags |
|---|---|
| https://medium.com/secbit-media/a-disastrous-vulnerability-found-in-smart-contracts-of-beautychain-bec-dbf24ddbc30e | third party advisory exploit |
| https://twitter.com/OKEx_/status/987967343983714304 | third party advisory |
| https://www.reddit.com/r/ethereum/comments/8esyg9/okex_erc20_bug/ | third party advisory issue tracking |
| https://dasp.co/#item-3 | third party advisory exploit |
| https://peckshield.com/2018/04/22/batchOverflow/ | third party advisory exploit |
| https://support.okex.com/hc/en-us/articles/360002944212-BeautyChain-BEC-Withdrawal-and-Trading-Suspended | third party advisory |