アスクル株式会社Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 31, 2025
- Severity
- BIncidents centered on names and contact details.
- Scale
- Unknown
- Main impact
- Due to a ransomware attack, some files on the server were leaked externally; it was reported that these may include corporate and consumer e‑commerce inquiry contact information and supplier information (names, email addresses, phone numbers, etc.).
- Information involved
- Email addressPhone numberFull name
- Cause / key point
- It was confirmed that some files on the server were leaked as a result of unauthorized access to the server accompanying the ransomware attack.About Ransomware
- Industry
- Retail & e-commerce
- Listing / capital
- Listed company東証プライム 2678(アスクル)
- Sources
- Last updated
- October 20, 2026
Stock price reaction to the disclosureアスクル / 東証プライム 2678
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Written & reviewed
Reviewed byYutaro SasaoFounder & CEO, MediaLeap Inc.
CEO of MediaLeap Inc. Working on both sides of web advertising and web media since 2013; founded the company in May 2025.
Review scope: cross-checking against primary sources (official and government announcements), verifying claims stay within the facts, and checking source attribution。Last reviewed:
Written by:Leak Watch editorial team (AI-assisted drafts verified against sources by the editorial team) · Reviewer profile · Request a correction
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Attack method classification: Ransomware(Encrypting data and demanding a ransom)
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