One example of the 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 or web bots can also be used to commit
click fraud and more recently have appeared around
MMORPG games as
computer game bots. Another category is represented by
spambots, internet bots that attempt to
spam large amounts of content on the Internet, usually adding advertising links. More than 94.2% of websites have experienced a bot attack. • Viruses and worms •
DDoS attacks •
Botnets,
zombie computers, etc. • Spambots that try to redirect people onto a malicious website, sometimes found in comment sections or forums of various websites •
Viewbots create fake views • Bots that buy up high-demand seats for concerts, operated by
ticket brokers who resell the tickets. These bots run through the purchase process of entertainment event-ticketing sites and obtain as many seats as they can. • Bots that are used in
massively multiplayer online role-playing games to farm for resources that would otherwise take significant time or effort to obtain, which can be a concern for online in-game economies. • Bots that increase traffic counts on analytics reporting to extract money from advertisers. A study by
Comscore found that over half of ads shown across thousands of campaigns between May 2012 and February 2013 were not served to human users. • Bots used on internet forums to automatically post inflammatory or nonsensical posts to
disrupt the forum and anger users. in 2012, journalist Percy von Lipinski reported that he discovered millions of bots or botted or pinged views at CNN
iReport.
CNN iReport quietly removed millions of views from the account of iReporter Chris Morrow. It is not known if the ad revenue received by CNN from the fake views was ever returned to the advertisers. The most widely used anti-bot technique is
CAPTCHA. Examples of providers include
Recaptcha, Minteye,
Solve Media and NuCaptcha. However, captchas are not foolproof in preventing bots, as they can often be
circumvented by computer character recognition, security holes, and outsourcing captcha solving to cheap laborers. == Protection against bots ==