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.
Malwarebytes (software)
Malwarebytes (formerly known as Malwarebytes Anti-malware) is primarily a scanner that scans and removes malicious software, including rogue security software, adware, and spyware. Malwarebytes scans in batch mode, rather than scanning all files opened, reducing interference if another on-demand anti-malware software is also running on the computer.