A browser toolbar is an example of what type of malware?

Browser toolbars are sometimes examples of PUPs or potentially unwanted programs like spyware or adware. A worm is a type of malware that spreads on its own by exploiting vulnerabilities on network-connected systems. Once it infects a system, it will typically scan for other vulnerable systems and continue to spread. A RAT is a remote-access Trojan, and a rootkit is used to gain and keep administrative access.