“Validation Buffer Full” Error on a Bellagio Slot Machine

The Bellagio is one of ten Las Vegas properties owned by MGM Resorts International. On September 11, 2023, MGM Resorts confirmed a cybersecurity incident that forced the company to shut down portions of its computer systems, including hotel reservations, digital room keys, and slot machine networks, across its properties. The outage lasted roughly ten days and was later attributed to a ransomware group known as Scattered Spider, which used social engineering tactics to gain access to MGM's network. MGM estimated the attack cost the company about $100 million in lost revenue and remediation expenses. This Aristocrat Gaming machine displayed a "Host Disable - Validation Buffer Full" error, a symptom of the network validation system being taken offline during the outage.