A BIOS rootkit is primarily designed by computer hardware manufacturer for different administrative purposes such as BIOS updates, device registration, and other tasks. Traditionally, the BIOS rootkit was non-erasable and editable. Modern systems now come equipped with a modifiable rootkit, which is stored within an integrated flash memory. A BIOS rootkit is generally persistent, and is not affected by hard drive failure or replacement.

A BIOS rootkit can also be exploited by hackers and crackers to illegitimately gain access to a system. In such an event, it is infested with a malicious code, which is generally undetectable, although it can be removed by most anti-virus and security software.