From experience (was lead dev at company where sales let a bitlocker in and IT had mis-configured backup... which is normal for backup in most companies): It's

From experience (was lead dev at company where sales let a bitlocker in and IT had mis-configured backup... which is normal for backup in most companies): It's all about what the infected machines can access. When my employer got hit, the problem was that there were many shared drives that the infected machines could access, and these were bitlockered. People would run programs off a shared drive, and get infected from that... then everything that machine had access to would get bitlockered. Backup was implemented where clients would push files to an open share and the share was backed up. The backups were bitlockered as a result. The shared drives were on a mix of linux and windows servers, and mac users that had shared folders the sales team could access had that data bitlockered. So, Windows was involved - it's how the bitlocker got in, but honestly, it was an emailed binary the salesperson ran that started the fun. Incidentally, the dev team (mix of Windows, Linux, Mac) was completely unaffected because we did not have any open shares, remote access was done with SSH. We used a backup system that ran as a pull, where the machine being backed up could not directly access the backup store, so safe. So yeah, Windows involved, but the damage was more about what infected machine had write access to on the network.