While a single computer can accomplish billions of operations every second, multiple computers working together can accomplish far, far more. They can be used to run impossibly large calculations (for legal or illegal purposes), act as a massive number of human users to manipulate online polls or contests, increase traffic to a website in order to inflate advertising costs or overwhelm its systems, or even spread more malware across the net.
Botnets can also be used to obtain personal information from the infected users, either by searching files on the computer or logging keystrokes as you type. Once your computer has been taken over, the criminals controlling the botnet can direct it to do any number of illicit activities, often without you ever being aware of it.
Frequently Asked Questions
How does a botnet take over computers?
Botnets take over computers using malware, which may be contained in a file downloaded over the internet, an email virus, a corrupted computer on your network, or even a flash drive you used on an infected machine. Once the malware is activated, usually by opening a file or clicking a link in a spam email, the malware works in the background where it won’t easily be detected. Depending on the type of malware, it may try to access your personal files, utilize your Internet connection, or even send itself to others using your email account.
How can a botnet crash a network?
Computer networks all have bandwidth limitations, meaning they can only send and receive so much information before everything grinds to a standstill. By directing enough traffic to a particular network, botnets can exceed those limits, making the network useless to other visitors. If you imagine a network as a busy intersection, a botnet essentially redirects as much traffic as it can to that intersection, creating impassible congestion. For Internet sites, this type of Denial of Service (DoS) attack usually involves directing thousands or even millions of infected machines at a single website, overwhelming its servers.
How can I keep my device safe?
Any computer or mobile device can be a target for botnets, but there are some easy steps you can take to limit your chances of getting infected. The most important action you can take is to make sure your operating system is up-to-date. Most operating systems give you an option to automatically apply new updates. Make that happen! If a vulnerability is discovered, you want your computer to fix itself before anyone can take advantage of it. Next, make sure your browser, email client, and any other program you use to access the Internet is up-to-date too. Once everything is updated, install a good antivirus program and make sure your computer’s firewall is active. For more information about protecting your computer, see our Stay Safe section.