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Casio confirmed that ransomware attackers accessed some of its servers on October 5, 2024, making several systems unusable and leaking some internal documents. Those documents included personal information about 6,456 employees and 91 customers. Casio said it found no evidence that attackers stole data from its customer database or the system handling customer personal information.
What happened in the Casio cyberattack?
Casio said a system failure occurred on some servers on October 5, 2024. The company found signs of unauthorized access, brought in an outside security specialist, and disconnected affected servers from both the internet and its internal network.
Casio’s public notices described how its understanding developed:
- October 8, 2024: Casio reported unauthorized network access and that some services were unavailable. Casio’s initial notice.
- October 11, 2024: Casio said ransomware had damaged systems and disclosed that some personal and confidential internal information may have leaked. Casio’s ransomware and service-outage notice.
- January 7, 2025: Casio published its investigation results, including the reported scope of leaked information and systems it said were not affected. Casio’s investigation update.
In that final update, Casio said servers had been accessed from overseas and ransomware had made several systems unusable. The company attributed the incident to deficiencies in its phishing-email measures and global network security arrangements, including those at overseas offices. Casio did not identify a specific phishing email, exploited vulnerability, or initial-access technique.
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What information did Casio say was leaked?
Casio’s January 7, 2025 update confirmed that leaked internal business documents contained personal information about employees and some customers. The company published these counts:
| Group | People affected | Details Casio listed |
|---|---|---|
| Employees, including temporary and contract employees | 6,456 | Included human-resources information for 5,509 domestic employees, such as names, employee numbers, email addresses, and affiliations. |
| Customers in Japan | 91 | For customers who bought products requiring delivery and installation: delivery address, name, telephone number, purchase date, and product name. |
Casio also said leaked internal documents contained information about some business partners and customers, whom it was identifying for individual contact. The company said the confirmed leaked personal information did not include credit-card information.
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Was the Casio customer database stolen?
Casio said it found no evidence that data had been stolen from its customer database or from the system handling customers’ personal information. The confirmed leak involved information in internal business documents; it was not a confirmed theft of the full customer database. Casio’s exact wording was: “No evidence of data theft was found in the customer database or in the system that handles customers’ personal information.”
Was CASIO ID affected?
Casio said CASIO ID and ClassPad.net ran on systems separate from the servers accessed in the incident and were not affected. That statement addresses those named services; it does not establish the status of every Casio service or the circumstances of every individual account.
Rank #3
- Natural Textbook Display presents formulas and results exactly as written in textbooks for intuitive learning.
What did Casio say about service recovery?
In its January 7, 2025 update, Casio said services suspended because of system failures had resumed except for some individual services. That is the status Casio reported on that date, not confirmation of service availability today.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How did Casio respond?
Casio said it consulted police on October 6, 2024, and Japan’s Personal Information Protection Commission on October 7, then made a report by October 9. It said it submitted a confirmation report to the Commission on December 3, 2024.
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- ADVANCED MATH OPTIONS: Perform trigonometric and inverse trig operations, permutations, combinations, factorials, and more. Choose your decimal settings for consistent results and easier grading or reporting.
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The company said it had not responded to unreasonable demands from the ransomware group. It also said it would strengthen security across the group, including at overseas offices, review information management, and reinforce internal training.
Quick Recap
Best Value
- COMPACT & PORTABLE DESIGN – Space-saving design that fits easily on any desk or in a briefcase, making it ideal for both home and office use.
- LARGE EIGHT-DIGIT DISPLAY – Clear and easy-to-read 8-digit display, perfect for everyday calculations, ensuring accurate results in home or office settings.
- GENERAL PURPOSE CALCULATOR – Ideal for a wide range of applications, from basic math to business and personal use.
- DUAL POWER SOURCE: Operates on solar power with battery backup to ensure reliable use in any lighting condition.
- DURABLE HARD COVER: Built-in protective case shields the calculator from scratches, drops, and everyday wear.
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