# Data Breach at GMO Internet: Customer Information Posted Online

*Published October 28, 2026*
*Source: [https://techcrunch.com/2026/10/27/japan-internet-giant-gmo-says-hackers-posted-stolen-customer-data/](https://techcrunch.com/2026/10/27/japan-internet-giant-gmo-says-hackers-posted-stolen-customer-data/)*

## Executive Summary

GMO Internet is investigating a data breach involving its Onamae Desktop Cloud service, with customer data allegedly posted online following unauthorized access. The company is working to assess the extent of the breach and has urged clients to reset passwords while offering compensation and alternative services.

## Article

GMO Internet, a major player in Japan's IT and internet services sector, is grappling with a significant security breach involving its Onamae Desktop Cloud service, primarily used by financial traders. The company is currently investigating the unauthorized access to its virtualized desktop service and has confirmed that some customer data has been posted online by attackers. While the full scope of the breach remains under scrutiny, GMO Internet has urged its customers to reset their passwords as a precaution after reports of unauthorized activities on trading accounts.

Approximately 27,000 servers may be implicated in this security incident, although the exact details are still pending verification. This breach follows recent findings by GMO's cybersecurity unit that identified the use of a Chinese AI-enabled tool named Artex in several cyberattacks across Japan and South Korea. However, GMO has not officially linked Artex to the Onamae breach.

The company took swift action after discovering the unauthorized access on October 21, shutting down the affected service and receiving a ransom demand from the hackers. By October 22, the incident was reported to the police, and GMO had begun working with government agencies to manage the fallout. To mitigate the impact, GMO has offered compensation and alternative services to its customers. As part of its ongoing efforts to understand and resolve the incident, the company started collecting devices from customers to check for malware by October 25.

In response to the increasing cyber threats, Japan's Financial Services Agency had earlier issued guidance to financial institutions to bolster their cybersecurity defenses. The agency recommended measures such as vulnerability management and incident preparedness, encouraging the use of AI and other advanced security tools.