The vulnerabilities in the systems are many and new ones are discovered every day. It may be difficult to fix all the errors, which is why It is important to focus on at least the most important things for hackers. That is, what criminals prefer and looking to be able to break into victims’ systems. Hackers create exploits for vulnerabilities and often sell to other criminals. A one-year study in underground forums shows that scammers are more interested in Microsoft vulnerabilities (followed by Adobe). The researchers observed that these exploits are the ones that are sold the most in underground markets and the ones that are most in demand.