Predictable Random Number Generation in PayWinner Function of Ethereum Lottery Smart Contract

CVE-2018-15552 · HIGH Severity

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

The "PayWinner" function of a simplelottery smart contract implementation for The Ethereum Lottery, an Ethereum gambling game, generates a random value with publicly readable variable "maxTickets" (which is private, yet predictable and readable by the eth.getStorageAt function). Therefore, it allows attackers to always win and get rewards.

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