What Are Bots and Botnets?

Bots quietly run a huge share of the internet. Some are helpful, like the search engine crawlers that index this page. Many are not. When malicious bots are linked together into networks called botnets, they become one of the most powerful engines of online fraud, capable of knocking sites offline, breaking into accounts, and faking traffic at massive scale. This guide explains what bots and botnets are, how they work, what they are used for, and how to detect bot activity before it causes damage.

What is a bot?

A bot is a software program that performs automated tasks over the internet, usually faster and at far greater volume than a person could. The name is short for robot, and the comparison fits: a bot follows instructions to carry out a repetitive action, whether that is indexing web pages, answering chat messages, or hammering a login form with stolen passwords. Bots are not inherently good or bad. What matters is who runs one and why.

Good bots vs. bad bots

Plenty of bots make the internet work. Search engines like Google and Bing use crawlers to discover and rank content, monitoring services use bots to check whether sites are online, and many companies run chat and support assistants. These good bots identify themselves and respect the rules a site sets.

Bad bots do the opposite. They disguise themselves as real users, ignore those rules, and exist to abuse a service rather than use it. In fraud and security, the word bot usually refers to this malicious kind: automated traffic built to steal, cheat, or disrupt.

What is a botnet?

A botnet is a network of devices that have been infected or compromised so they can be controlled remotely by a single operator, often called a bot herder. Each infected device, sometimes called a zombie, keeps working normally for its owner while quietly taking orders in the background.

The operator issues those orders through command-and-control infrastructure. Older botnets relied on a central server, while modern ones often use decentralized, peer-to-peer control that is harder to shut down. A botnet can pull together almost anything with an internet connection, from home computers and routers to poorly secured IoT devices and cloud servers, sometimes reaching hundreds of thousands of machines at once.

How devices get pulled into a botnet

Devices are usually recruited through malware. Common routes include phishing emails with malicious attachments or links, drive-by downloads from compromised websites, software that hides malware inside something that looks legitimate, and unpatched or default-password IoT devices that attackers can take over directly. Once the malware is installed, the device connects back to the operator and waits for instructions, and most owners never notice anything is wrong.

What botnets are used for

A single bot is a nuisance. A botnet is a weapon, because it multiplies one attacker into thousands of coordinated sources. The most common uses include:

•       DDoS attacks. Many devices flood a target with traffic at once, overwhelming it until legitimate users cannot get through. Distributed denial-of-service attacks are the classic botnet calling card.

•       Credential stuffing and account takeover. Botnets test stolen username and password combinations across many sites at once, then seize the accounts that match.

•       Spam and phishing. Botnets send mass email and messages that spread scams and more malware while hiding the true source.

•       Ad and invalid traffic fraud. Bots generate fake clicks and impressions to drain advertising budgets and inflate fraudulent payouts.

•       Fake accounts and abuse. Botnets mass-create fake accounts to claim signup bonuses, post spam, or scrape content at scale.

•       Residential proxy abuse. Increasingly, operators monetize infected devices by renting them out as residential proxies, letting other fraudsters route traffic through real home IP addresses to look legitimate.

A real-world example

Botnets are not theoretical. The AIRASHI botnet, for instance, has been used to launch powerful DDoS attacks and to feed residential proxy networks, exactly the kind of dual-purpose abuse described above. Tracking live campaigns like it is part of how threat intelligence keeps detection current.

How to detect and defend against bots and botnets

Because botnet traffic comes from many real devices and IP addresses, you cannot stop it with a simple block list. Effective defense layers several signals together:

•       Checking IP reputation to flag addresses tied to known botnet and proxy activity.

•       Watching for automated behavior, such as impossible speed, repetition, and patterns no human would produce.

•       Fingerprinting devices to spot the emulators, virtual machines, and tampered setups that bots run on.

•       Applying bot mitigation that scores each visitor in real time and acts before damage is done.

For a deeper, practical walkthrough, see our guide to botnet detection best practices.

Frequently asked questions

What is the difference between a bot and a botnet?

A bot is a single automated program. A botnet is a large network of infected devices controlled together by one operator so they can act in unison.

Are all bots bad?

No. Search crawlers, monitoring tools, and chat assistants are legitimate bots. The malicious kind disguises itself as a real user to commit fraud or abuse.

What is a botnet used for?

Most commonly DDoS attacks, credential stuffing, spam and phishing, ad fraud, fake account creation, and reselling infected devices as residential proxies.

How do I know if bots are hitting my site?

Look for traffic spikes, abnormal speed and patterns, and connections from flagged IP addresses. You can test your traffic against bot detection to see what automated activity is already reaching you.

Stop malicious bots before they reach your users

Bots and botnets are constant, but they are not unstoppable. Start a free trial with 1,000 free lookups per month, or schedule a demo to see how IPQS detects bots and botnet traffic in real time.