What Is a Bot?

Bots are everywhere on the internet, hiding in places you may least expect them. But is that really so bad? Keep reading to learn how bots work, what different types of bots are used for, and how to spot and remove malicious bots with powerful anti-malware software like Avast One.

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Written by Domenic Molinaro
Updated on October 16, 2023

What is a bot?

A bot (short for robot) is a software application programmed to perform tasks through Robotic Process Automation, or RPA. Bots work by automatically going through a set of instructions, and they carry out tasks and processes much faster, more accurately, and at a higher volume than it would otherwise take humans.

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    You can define a bot by looking at its RPA instructions, called a script. Crawl bots used for search engines, for example, are scripted to “crawl” across the internet like a spider, sending any new info they find to search engines. Spam bots, meanwhile, are designed to send people spam — like those annoying emails you get sometimes.

    Bots were once seen as generally helpful, because they can quickly execute difficult tasks like complicated calculations and complex algorithms. But the core bot meaning is shifting as hackers increasingly use bots for spying, viruses, and exploiting vulnerabilities in computer software or hardware. Today, most people’s definition of a bot has a negative undertone.

    Bot attack definition

    A bot attack is a type of cybercrime where hackers use automated scripts to wreak havoc, steal data, or carry out other malicious activity. Bot attacks are a particularly efficient and dangerous cyberthreat that can target a variety of endpoints including websites, server infrastructure, APIs, and more.

    Automated bots are a menace, reportedly responsible for about half of internet traffic. Bot interactions are often hard to distinguish from human ones, but learning how bots work and what they do can help you avoid being deceived and infected by the malicious types of bots.

    How do bots work?

    Bots usually have a predefined trigger that tells them to start working, such as a particular keyword or an event like a message sent on social media. Once triggered, internet bots communicate with each other through internet-based interactions, completing the tasks they were scripted to do via automation, computer vision, and machine-learning.

    Automation is the process of doing tasks without human intervention. Computer vision is the attempt to understand and copy the human visual system through digital images and videos, while machine-learning is the ability to extrapolate trends from patterns in data and make adaptations accordingly.

    The processes a bot performs must be ruled-based and logical, with well-defined inputs and outputs. Anything too complicated is outside a bot’s purview.

    Are bots good or bad?

    Bot software can be used for both good and bad purposes. Plenty of bots provide legitimate benefits to users, while many bots are designed to install spyware or steal sensitive data. A good bot can answer your questions quickly or show you relevant search results, while a bad one could spear phish you.

    Many hackers use bots because they’re so effective at doing their dirty work for them. A bot attack is a type of cybercrime where hackers use automated scripts to wreak havoc, steal data, or carry out other malicious activity. Bot attacks are a particularly efficient and dangerous cyberthreat that can target a variety of endpoints including websites, server infrastructure, APIs, and more.

    As bot technology advances, new bot types are created. There are many breeds of computer bot, both legitimate and malicious. Some bots can fit into either category.

    Some bots help websites run efficiently, and some are used for spying and phishing. Some bots can do both.Legitimate bots can help websites run more efficiently, while malicious bots can help hackers avoid detection.

    Types of legitimate bots

    Some bots are legitimate and improve website performance and use experience across the internet. Other bots are only technically legitimate, but in fact occupy legal and ethical gray areas — mainly serving the self-interests of their operators.

    Here are some legitimate bot types:


    Chatbots simulate human conversation through text or voice, and are often used to answer frequently asked questions or other basic (level-one) communication about a product or service. Chatbots like Apple’s Siri or Amazon’s Alexa are called “knowledge chatbots,” since they offer general knowledge.

    Chatbots can usually message a real person if the user asks, but if a chatbot is owned by a hacker, it can be used to phish for private details or trick people with social engineering schemes.


    Crawl bots, also known as crawlers or web spiders, browse the internet rapidly, indexing all the content they come across. The information is then processed and sent back to a search engine provider, like Google. A crawler can take anywhere from a day to a few months to index new content, depending on how powerful the crawler is and how deep it’s designed to go.

    For example, when a website publishes new content, it can take Google’s crawl bots anywhere from a few hours to a few weeks to index the new content, depending on how easy it is for Google to find and index the site.


    Scrapers are a type of crawler that strips (or scrapes) websites for certain kinds of data. Scraping helps drive traffic to a site or display relevant information to potential customers by gathering their user data. Scrapers can also be used to plagiarize content or steal credit card numbers.

    Shopping bots

    Shopping bots automate browsing and checkout processes. They can also search for the best deal available and alert the bot owner. A common use of shopping bots is to buy massive quantities of a popular item after it’s released, then cash in on the resale market. This use of a shopping bot is outlawed in certain circumstances, such as the market for concert tickets in the US.

    Social media bots

    Spam bots are automated programs designed to mimic the activities of human users on social media platforms. Although social media bots have lots of legitimate and useful applications, like providing live weather updates and sports scores, they can also be used for trolling, spreading fake news, cryptocurrency fraud, and other scams.

    Monitoring bots

    Monitoring bots maintain the health of a website by reporting bugs or vulnerabilities back to the site owner. They are the worker bees of the botworld, buzzing around a website and reporting if anything is wrong. Monitoring bots can also be programmed to monitor user activity on a website.

    Sometimes monitoring bots can be used to spy on web visitors. So periodically check and remove spyware on your PC in case a webpage has set its sights on you.

    Transaction bots

    Transaction bots let you complete financial transactions. They can verify your identity, block your credit card if it’s been stolen, complete a purchase, and perform other financial services. Credit card processors, checkout desks, and PIN authenticators all fall under transaction bots. Transaction bots process large volumes of highly sensitive financial information, and are highly secure — but they’re also big targets for hackers looking to hit the jackpot.

    Types of malicious bots

    When are bots legal, and when are they not? Though some legitimate bots may skirt ethical boundaries, malware bots that damage computer systems, steal credentials, or carry out other dangerous activities are strictly illegal.

    Here are some malicious bot types:


    Spambots send waves of infected material wherever they can, whether via email, on a website or social media site, or through an instant messaging app. Some spam is meant to spy on you or take your data, while other spam is loaded with adware, bloatware, or other junk.

    Voice bots

    Voice bots are expensive hacking tools that fraudsters use to steal 2FA (two-factor authentication) or OTP (one-time password) codes for private accounts. 2FA and OTP codes have become commonplace for password retrieval and payment authentication, and many people let their guard down when a voice bot requests their code.

    To avoid being victimized by voice bots, create and use strong passwords and manage them with a secure password manager.

    File-sharing bots

    File-sharing bots spy on people’s search queries and provide bogus links to requested items. When you click on the link, your device can get infected with a computer virus or other types of malware.

    These bots can be especially tricky to avoid, but good antivirus software can detect either a virus or other malware program if you accidentally click an infected link. For more insidious malware, like Trojans, using a Trojan remover tool should clear it right up.

    Credential stuffers

    Credential stuffers spam known or suspected login details at a high volume of accounts hoping to get a match. After uncovering authentic credentials through data breaches or brute force attacks, cybercriminals set credential stuffer bots loose to log in wherever possible.

    DDoS bots

    DDoS bots flood a website with requests to try to overwhelm it into crashing. A network of botnets can work together to take down an entire website with a DDoS attack. DDoS bots can hold a site hostage until the hacker’s demands are met. Botnets wreak havoc on businesses and are a favorite tool for many hacker groups.

    Vulnerability scanners

    Vulnerability scanners assess networks, individual devices, and apps for weaknesses that can be exploited. Vulnerability scanners are similar to monitoring bots, but are designed specifically to find security holes.

    Click fraud bots

    Click fraud bots, or click bots, generate fake views for pay-per-click ads, social media posts, search engines, and anything else that relies on clicks for financial or algorithmic gain. Click bots pass themselves off as human clicks, making it seem like the engagement they generate is real.

    Advanced click bots can be scripted to post comments or conduct other human-like internet activity to trick website owners and advertisers into thinking their content is more successful than it actually is.

    How to tell if your computer is infected

    Malicious bots can infect your computer in various, often sneaky ways. It’s easy to confuse signs of a virus or other kinds of malware infection with general wear and tear.

    Some telltale signs of computer infection include:

    • Unexpected crashes

    • Sluggish performance

    • Strange applications

    • Unwanted pop-ups

    • Loud computer fans

    • Missing files

    • Problems shutting down or restarting

    • Error messages

    There could be other reasons your computer keeps crashing, but you can prevent bot attacks by creating a common sense security system for your device.

    How to prevent malicious bot activity

    Learning what cybersecurity is can keep bot attacks off your back. Hackers rely on their victims not knowing how to stay safe.

    A good firewall can be the first line of malicious bot protection. Many bots will turn around at a firewall and go elsewhere. If a malicious bot happens to find its way inside your network, download a VPN to stay invisible. And get a strong malware removal tool that can do a bot scan and remove any malicious bots planted on your device before they compromise your security.

    Protect your system against bots with Avast

    Bots can be wily and nearly indistinguishable from humans, so you need powerful anti-malware software from a reputable provider.

    Avast One features a built-in, intelligent firewall to detect deceptive bots. It’ll scan your machine for any traces of malware, including malicious bots, and sweep them away in no time. It’ll also block viruses, ransomware, and prevent hackers from getting into your system and accessing your personal data.

    Avast will monitor your security 24/7, beating any bots that come sniffing around. Get One for free today.

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    Domenic Molinaro