CVEvulnerability

CVE-2018-17071

7.5 HIGH Published 2018-09-18 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2018-09-18
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.0 ([email protected])
7.5 HIGH — CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0 ([email protected])
5.0 MEDIUM — AV:N/AC:L/Au:N/C:P/I:N/A:N
Weaknesses
CWE-338

Description

The fallback function of a simple lottery smart contract implementation for Lucky9io, an Ethereum gambling game, generates a random value with the publicly readable variable entry_number. This variable is private, yet it is readable by eth.getStorageAt function. Also, attackers can purchase a ticket at a low price by directly calling the fallback function with small msg.value, because the developer set the currency unit incorrectly. Therefore, it allows attackers to always win and get rewards.

Affected configurations

• lucky9 lucky9io

Related

Weakness · CWE (1)

  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) weakness

References