Virus is a name of malware variety. I’m not sure what the purposes of the virus (computer virus) or what is the benefit of it’s creator. According to the few source that i have read before, a virus could deploy themselves on the system. For some viruses, we will not find or detect the effects on the device who has infected by them, but the other virus could make a fatal damage on the device by wrecking the system of the device. But usually we can detect virus if we’ve found that the disk space has decreased significantly, because the virus can multiply themselves.
Worm is another various name of malware. In my opinion, worm is not too dangerous for computer or another device because i think the attacking method is not too dangerous. Correct me if i’m wrong. Worm can multiply themselves just like virus.
This malware is a “hidden” programs, disguising themselves as an application or program (software) that can be useful for the device users, whereas in that program or apps is containing another malware such as worm or virus that intending to attack the device system. It can be more dangerous if in that Trojan Horse malware is containing a spyware that eventually will steal your personal data such as Bank account or passwords.
As its name “spy”, this malware is intended to snoop into the device who has infected by it. And for the next step, the information that has been stolen from you will be sent to the spyware maker, so they could take over your accounts easily.
And there’s still many various of malware that we can found such as backdoor, hijacker, botnet, dialer, rootkit, adware, wabbit etc. For you smartphone users especially Android smartphones, i have some tips for you to avoid malware on smartphone. Just click that link and check it out!