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[Contained][Severity: Moderate][Intrusion][Malware]

GMO Internet: attackers planted malicious programs on some ConoHa WING servers, affecting data in the web server areas of 426 customers

From September 3, a third party planted malicious programs on some ConoHa WING rental-server hosts at GMO Internet, affecting the web areas of 426 customers.

Disclosed

2026-09-20

Organizations involved

1

Leaked or at risk

Unknown

Downtime

Unknown

What happened

  1. Unauthorized access to customer areas began on some hosts and malicious programs were placed. [1]

  2. GMO Internet announced the unauthorized access. [1] [2]

Impact

The data affected is that stored in the web server areas of 426 customers on the hosts concerned. [1] [2]

Timeline

  1. Started 2026-09-03
  2. Disclosed 2026-09-20
  3. 17 days

Attack or cause

Method
[Intrusion][Malware]
Impact
Entry point
Unknown

Data exposed or at risk

–

Organizations involved

  • [Breached][Moderate]Tokyo, ShibuyaInformation and communications

    GMO Internet, Inc.

    Some hosts of the ConoHa WING rental-server service were accessed without authorization and malicious programs were placed in customers' web server areas.

Open in organization search

Sources

  1. [1][Official]【重要】[ConoHa WING byGMO]一部収容ホスト（Webサーバー）への第三者による不正アクセスに関するお詫びとお知らせGMO Internet, Inc. · 2026-09-20
  2. [2][News]ConoHa WING byGMO に不正アクセス、不正プログラムを設置ScanNetSecurity · 2026-10-14 08:05