https://www.theregister.co.uk/2019/04/10/kcl_mass_password_reset/

Exclusive King's College London has suffered an IT worry but this time not of its own making – yesterday it warned staff and students that some accounts have been "compromised" due to an apparent brute-force attack on password systems.

The Register has been informed that the raid, which has been ongoing for several days, originates in China and is targeting accounts on the university's Microsoft Office 365-hosted systems.