GMO Internet Group,
"GMO Security 24" Conducts Emergency Diagnosis and Alert for 70,000 Registered Email Addresses in Regular Diagnostic Service

GMO Internet Group has conducted an emergency leak diagnosis targeting approximately 70,000 email addresses registered for regular diagnostics in "GMO Security 24," a service provided by GMO Internet Group. This action was taken in response to newly registered large-scale password leak information ^(※1) discovered on the internet. As a result, 350 newly identified compromised addresses were confirmed, and prompt alerts were issued to the affected customers.

Moving forward, GMO Internet Group will continue to strengthen initiatives to improve the safety of customers' internet usage under the mission of "A safer future for Everyone"

(※1) Approximately 690,000 cases previously disclosed in August 2022

Background of Implementation

We confirmed that approximately 690,000 leaked data cases disclosed in 2022, which could potentially affect "GMO Security 24" customers, were registered in a leak database. Judging that addresses not initially confirmed might be newly included, we urgently conducted a re-diagnosis of addresses registered for regular diagnostics in "GMO Security 24."

Implementation Details

• Target:
Approximately 70,000 email addresses with regular diagnostic settings turned ON in "GMO Security 24"

• Method:
Proprietary diagnosis to match newly registered leak data on the internet with registered email addresses

• Results:
Confirmed that 350 email addresses were newly subject to leaks

• Response:
Individual alert emails were sent to affected customers, providing guidance on necessary measures such as password changes and prevention of password reuse across other services

GMO Internet Group will continue to promptly conduct necessary diagnostics and alerts when new risks such as large-scale leak information are confirmed, striving to ensure password security and prevent damage to our customers.

About "GMO Security 24"(https://www.gmo.jp/security/)

"GMO Security 24" is the world's first ^(※2) comprehensive internet security service that provides 24-hour free diagnosis of information leaks and security risks simply by entering email addresses or website URLs.

Main features include:

■ Password leakage diagnosis
Diagnoses whether registered email addresses have been leaked in the past. When new leak information occurs, automatic checking and notification are conducted through the regular diagnostic function. Also provides "Regular Diagnostic Function" once a month and "Emergency Diagnostic Function" when new leaks occur.

■ Web risk diagnosis
Comprehensive diagnosis of vulnerabilities and risks for your own websites or specified URLs.
Also provides "Regular Diagnostic Function" once a month and "Emergency Diagnostic Function" when high-risk vulnerabilities are discovered.

■ Security Consultation AI
24-hour automatic response to security questions and concerns.

(※2) As of February 2025, according to company research

" GMO will protect your Internet Security " Project

The " GMO will protect your Internet Security " Project started in February 2025 under the mission of "A safer future for Everyone" aiming for an internet society where everyone can connect with peace of mind, and will provide various security-related measures on the internet.

■ Phase 1: Launch of "GMO Security 24"
https://www.gmo.jp/security/

■ Phase 2: "GMO Cybersecurity Conference & Awards 2025"
https://www.gmo.jp/security/conference/2025/

■ Phase 3: Launch of "GMO '.YourCompanyName' Application & Operation Support Service"
https://group.gmo/security/yourbrand/

GMO Internet Group's Internet Security Business

Of GMO Internet Group's approximately 8,000 partners (employees), about 1,100 are involved in the internet security business. We provide customers with various internet-related security services based on three pillars: "Prevention of eavesdropping, tampering, and impersonation; strengthening login authentication," "Cyber attack countermeasures," and "Impersonation monitoring and deletion support."

(Reference: History of GMO Internet Group Security Business
https://www.gmo.jp/security-history/)

Note : This document has been translated from the Japanese original for reference purposes only. In the event of any discrepancy between this translated document and the Japanese original, the original shall prevail.