There are security risks associated with browsing the Internet. Three of these are listed below.
Cookie
A cookie is a text file that a web server stores on your hard drive and later retrieves whenever you visit that site. When you return to that site, the cookie recognizes you, saving you the trouble of reregistering. The problem with cookies is that the site can potentially track your activities on the web. Your browser can be set to not accept cookies.
Mobile Code
Mobile code, such as ActiveX and JavaScript, are scripting languages used for Internet applications. Mobile code embedded in a web page can recognize and respond to user events such as mouse clicks, form input, and page navigation as well as play audio clips. However, JavaScript and ActiveX do introduce some security risk, because they can cause hostile programs to be automatically run on your computer, just because you visited a Web page. The downloaded program could try to access or damage the data on your machine, or insert a virus.
Denial of Service
Another threat in Internet security is the Denial of Service
attack. These attacks involve bombarding a web server with huge amounts of data
from many different machines and locations in an effort to bring the server
down and deny its availability. The attacks can be launched from systems across
the Internet unified in their efforts, or, by compromised systems that are controlled
by servers which can hide the true origin of the attack.