Cookies normally do not compromise security, but there is certain malicious cookies. These types of cookies can be used to store and track your activity online. Cookies that watch your online activity are called malicious or tracking cookies. These build a profile of your interests. Once that profile contains enough information there is a good chance that your information can be sold to an advertising company who then uses this profile information to target you with interest specific adverts. Many antivirus today will tell you if a malicious cookie is tracking your info.
Phishing is when someone or something steals your personal information online. For example a website may have no link to a phishing site although it may be advertised on there site. A example of phishing is when websites claim that you are a significant viewer, they may tempt you into a fishing link through the promise of free items or that your information may have been stolen and that you must sign in via their link that way they acquire your info and can steal certain information from you.
A virus is a software that duplicates itself within the boot drive of a windows PC.by attaching its self to a certain files.Viruses often perform some type of harmful activity on a infected system such as stealing hard drive space or CPU time, accessing private information, corrupting data, displaying stupid messages on the user's screen, or logging the users keystrokes.