I nternet bots are software applications that are used on the Internet for both legitimate and malicious purposes. Because of the increasing number of applications becoming available online, there are many different types of Internet bots that assist with running applications such as instant messenger and online gaming applications as well as analysis and gathering of data files.
Search engines use bots to index Web pages for ranking in search results. Bots are also used for delivery of media and live streaming for different types of browsers. Hackers also use bots to perform malicious acts on the Internet and to breach the security of PCs through the installation of malicious files.
Types of Legitimate Bots
There are many different types of bots that perform legitimate tasks on the Internet that would otherwise take a person a long time to execute. These types of bots serve a purpos and act as a time saver for different applications.
Spider Bots: These are used by the search engines to explore Web pages for content, organization and linking.
Spider bots have certain criteria for indexing and determine the ranking of Web pages within the search results.
Trading Bots: These are bots that spider the online auction sites to locate the best deals on a specific product or service. In this case, a trading bot is used for commercial gain.
Another, more malicious use of bots is the coordination and operation of an automated attack on networked computers, such as a denial-of-service attack by a botnet. Internet bots can also be used to commit click fraud and more recently have seen usage around MMORPG games as computer game bots. A spambot is an internet bot that attempts to spam large amounts of content on the Internet, usually adding advertising links.
There are malicious bots (and botnets) of the following types:
Spambots that harvest email addresses from contact forms or guestbook pages
Downloader programs that suck bandwidth by downloading entire web sites
Web site scrapers that grab the content of web sites and re-use it without permission on automatically generated doorway pages
Viruses and worms
Botnets / zombie computers; etc.
Bots are also used to buy up good seats for concerts, particularly by ticket brokers who resell the tickets. Bots are employed against entertainment event-ticketing sites, like TicketMaster.com. The bots are used by ticket brokers to unfairly obtain the best seats for themselves while depriving the general public from also having a chance to obtain the good seats. The bot runs through the purchase process and obtains better seats by pulling as many seats back as it can.
The most widely used anti-bot technique is the use of CAPTCHA, which is a form of Turing test used to distinguish between a human user and a less-sophisticated AI-powered bot, by the use of graphically encoded human-readable text.
Media Bots: Media bots are used to provide updates on weather conditions, news and sports, currency exchange, and are used as censors in applications that run chat rooms and instant messenger programs.
Types of Malicious Bots
Bots are also used in a variety of ways to perform malicious acts and network security breaches.
Spam Bots: This type of bot spiders the Internet for the purpose of collecting data from forms that have been filled out online, spreading advertisements and pop-ups throughout the Internet, and collecting email addresses for the purpose of spamming.
Hacker Bots: Hackers use this type of bot to crawl around the Internet and find vulnerabilities in websites and online applications so they can exploit them for malicious purposes.
Botnets: Botnets are networks that hackers set up online by using "zombie" computers to perform malicious acts such as denial of service attacks. Zombie computers are computers that have been taken over by the hacker without the knowledge of the PC owner.
Download Bots: These are bots that are used to forcibly download a Web page that the hacker wants the surfer to see instead of a Web page that the surfer requested.