ESET NOD32 Antivirus is antivirus software that protects from malware such as viruses, worms, Trojans, spyware and rootkits. Various types of malware use different approaches to infiltrate. Computer viruses, for example, are computer programs that replicate themselves by spreading from computer to computer. Worms take advantage of security vulnerabilities to spread over networks. Trojan horses pretend to be harmless until they arrive at a place where they can do damage.