Comodo Memory Firewall is a prevention tool which is free and prevents most (90+%) buffer overflow attacks. Buffer overflow attacks are difficult to detect because these attacks can be launched just by visiting a site. To attack a computer, a malicious program or script deliberately sends more data to its memory buffer than the buffer can handle. The system is vulnerable to malware that can reformat the hard drive, steal sensitive user information, or even install programs that transform the machine into a Zombie PC.”]
Source: https://www.darkreading.com/attacks-breaches/comodo-launches-memory-firewall