[URGENT] Forced Reset of SFC-CNS Login Passwords and Request for Reconfiguration
Notice and Apology Regarding the Potential Leak of Personal Information Due to Unauthorized Access (December 26, 2025)
This is an important announcement from the Shonan Fujisawa ITC and CSIRT.
Following the potential unauthorized access to the SFC-CNS mail system, we performed a forced reset of CNS mail passwords on December 23. For details regarding the background of this incident, please refer to the following announcement:
- [Emergency] Forced Password Reset Due to Potential Unauthorized Access to SFC-CNS Mail System
To ensure the prevention of data leaks and secondary damage, we will implement a forced reset (deactivation) of "CNS Login Passwords" today, as scheduled below, which we had strongly recommended changing in the previous announcement.
CNS Login Password: Password used to access various CNS services (including logging into computers in the PC rooms).
CNS Mail Password: Password dedicated to sending and receiving CNS emails.
1. Forced Reset of SFC-CNS Login Password
To prevent unauthorized access, we will force-reset the login passwords for all CNS accounts at the time mentioned above. All CNS services will become unavailable.
Please immediately perform "3. Procedure for Password Re-registration" yourself.
2. Who is affected by this measure?
-
All SFC-CNS users (including sub-account users)
However, those who changed their CNS login password during the following periods are excluded:- After 12:00 a.m. Nov 28, 2025, and before 12:59 p.m. Dec 23, 2025
- After 1:00 p.m. Dec 23, 2025, and before 11:59 a.m. Dec 25, 2025
3. Procedure for SFC-CNS Login Password Re-registration
If you are unable to log in to CNS services after the reset, please follow the steps below to re-register. The procedure differs depending on whether you have a keio.jp account.
The temporary password is valid until Monday, February 9, 2026.
Once this period expires, the temporary password can no longer be used.
A. Users with a keio.jp account (Students, Faculty, Staff, etc.)
Please re-register your password using the "Temporary Password" issued on keio.jp.
Please refer to
this page
(keio.jp authentication required) for the re-registration procedure.
If you have forgotten your keio.jp password, please bring your ID to the ITC counter at your nearest campus or contact us via the IT Inquiry Form .
B. Users without a keio.jp account
-
At the Counter: Please visit the Shonan Fujisawa ITC counter with a valid ID.
Refer here (https://www.sfc.itc.keio.ac.jp/en/contact_sfc.html) for the location and opening hours. - By Mail (SFC Research Institute members only): Temporary passwords will be sent to your registered address sequentially. Once received, use it to re-register your "CNS Login Password" on the site mentioned above.
SFC Research Institute members can also obtain a temporary password at the counter. In this case, please dispose of the document sent by mail yourself.
4. Password Policy and Preventing Secondary Damage
-
Do not use previous passwords:
Considering the possibility of leaks, please avoid using the same password as before or easily guessable patterns. -
Do not reuse passwords on other services:
If you use the same string as your CNS password for your keio.jp password or other external services (SNS, banking, etc.), we strongly recommend changing them immediately.
-
Use MFA (Multi-Factor Authentication):
Please consider setting up MFA for keio.jp. By enabling MFA, you can minimize damage even if your password is leaked.
https://sites.google.com/keio.jp/kmfa-info-1st-jp/
We apologize for the significant inconvenience and appreciate your understanding and cooperation in maintaining university-wide security.
Last-Modified: December 26, 2025
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