Malware
Malware authors target bugs, or loopholes, to exploit. A common method is exploitation of a buffer overrun vulnerability, where software designed to store data in a specified region of memory does not prevent more data than the buffer can accommodate being supplied. Malware may provide data that overflows the buffer, with malicious executable code or data after the end; when this payload is accessed it does what the attacker, not the legitimate software, determines.
Boot sector
As an example, the malware [[Petya (malware)|NotPetya]] attempts to gain administrative privileges on an operating system, and then would attempt to overwrite the boot sector of a computer. The [[Central Intelligence Agency|CIA]] has also developed malware that attempts to modify the boot sector in order to load additional drivers to be used by other malware.
[[Category:Computer file systems]]
[[Category:BIOS]]
[[Category:Booting]]