istyle@cosme

1MinorPossibleAnnounced

A file with emails, mailing settings and user IDs of 10,997 people was viewable from outside for about 20 minutes. The URL was shared only internally. Names were not included.

This incident was imported from a dataset that compiles public announcements, and we are still checking it against the sources. Counts and causes will be updated after the check. Sources are in Japanese.

Cause
Misconfiguration
Occurred
2026-09-02
Sector
Retail & e-commerce
Operational impact
None

Data involved

DataStatusCountGroupEvidence
Email addressWas publicly accessible10,997 people—Source(opens in a new tab)
User or member IDWas publicly accessible10,997 people—Source(opens in a new tab)

Counts are the figures the organization announced. Because the same person may be counted more than once, we do not add the rows together.

What users should do

  • Watch for emails and texts pretending to be the company

General steps based on the type of data involved. Check the organization’s notice or help line to see whether you are affected.

Tools for this kind of attack

Picked from the cause of the incident: tools that help you check your own systems for the same kind of weakness, or spot the warning signs.

Prowler

Impact Reaches others
prowler-cloud/prowler

An audit tool that reads the configuration of AWS, Azure, Google Cloud, and other clouds and lists the settings that fail security standards.

Purpose
Audit
Type
Command line
Difficulty
Intermediate
License
PermissiveApache-2.0
Category
Containers and cloud
Actively updatedstars15,094Last update 2026-10-25
Read the Prowler review

Trivy

Impact Local only
aquasecurity/trivy

A scanner that finds vulnerabilities, misconfigurations, and embedded secrets in container images, code, and Kubernetes.

Purpose
Defense
Type
Command line
Difficulty
Beginner
License
PermissiveApache-2.0
Category
Vulnerability scanning / Containers and cloud
Actively updatedstars38,703Last update 2026-10-23
Read the Trivy review

Sources

  1. @cosmeご登録の個人情報の漏えいの可能性に関するお知らせとお詫びwww.istyle.co.jp(opens in a new tab)