I find it hard to believe that your complex passwords got cracked overnight. Were your machines on the internet and do you have huge bandwidth, not behind a fir

I find it hard to believe that your complex passwords got cracked overnight. Were your machines on the internet and do you have huge bandwidth, not behind a firewall? Inside job perhaps with access to /etc/shadow with passwords shared across machines or something? perhaps user accounts got compromised by other users? that's a phenomenal number of login attempts across the internet.