This is s simple 512-byte MBR program that pretends to be Windows CHKDSK. It asks the user for a password, writes that password back to the media it booted from, renders that media unbootable, and reboots.

NOTE: Windows helpfully prompts the user to format the drive when its inserted, or…

http://www.toolswatch.org/2012/09/evil-maid-chkdsk-steal-users-password-with-fake-chkdsk/