We've had four customers in the last couple of weeks locked out of their Hikvision recorders by what looks like bot. All clients were on old firmware with default admin password of 12345 and default ports -I know, I know, they were all installs from years ago who we hadn't visited since. In all cases the admin password has changed and a new SYSTEM user has been added. Our Hikvision distributor has been inundated with pw reset code requests.
If you have any Hikvision users/clients on defaults I'd suggest contacting them and changing the admin password ASAP.