A bot is a program that automatically performs some action on computers instead of people. When talking about bots, we often mean those that are on the Internet.
Basically, bots are human helpers, capable of doing repetitive and repetitive work at a speed far beyond the capabilities of humans. Their help is also invaluable in conditions when a lightning-fast reaction to any event is required.
Most often you can find bots in chats or online games with the ability to communicate between players. They imitate living people, users sitting at other computers. Also, bots control the actions of numerous characters in MMORG and other online games. In online auctions and stock exchanges, bots have replaced a person when carrying out routine actions - buying up valuables, arbitration and scalping. Often, bot actions make up the lion's share of the intraday volume of transactions.
The owner of a site wishing to use bots for good purposes, or any other server maintenance specialist, can insert a Robots.txt file into the server and indicate in it the restrictions on the activity of bots. The bots themselves are obliged to obey these rules.
To effectively achieve their goals, malicious bots gather on the network (botnets) and populate computers with weak protection against malware. They penetrate the computer using Trojans. Examples of bots for sending spam, posting it on sites, processing text. Malicious bots carry out large-scale calculations to crack passwords and index network resources, steal personal data, bank card numbers and PIN codes. Some bots prepare a computer for a DDoS attack by weakening its defenses. In addition, all worms and some viruses are also bots.
Most computer users can easily distinguish a bot from a real human being. But for a machine, this is a daunting task. Therefore, the most effective means of fighting bots was invented - the reverse Turing test, colloquially called captcha. This is a specially processed text, easily readable by humans and completely inaccessible to machine understanding.