CVE-2018-17071 Information

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.

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Reference

https://github.com/TEAM-C4B/CVE-LIST/tree/master/CVE-2018-17071

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

7.5