Hackers can create botnets in many different ways, but they share the same objective: to hijack and target as many devices as possible. Learn how botnet attacks work so you can better protect yourself from zombie bots that are after your device. Then get reliable security software for powerful protection against malware and other online threats.
A botnet is a network of computers infected with malware that’s controlled by a cybercriminal behind a single master computer. The hijacked computers are used to carry out cyberattacks without the owners’ knowledge. The term “botnet” is a combination of “robot” and “network.”
There are two ways you can fall victim to this cyber threat: your device can either be ensnared in a botnet of infected computers, or you could find yourself being targeted by a botnet-powered attack.
Botnets rely on two elements to work: A large network of infected devices known as “bots” or “zombies” to carry out the attack, and a “bot herder” that controls the zombies during the attack.
Here’s how botnets are typically created:
A cybercriminal targets devices, perhaps by exploiting a vulnerability in software or by using social engineering tactics to gain access.
Botnet malware is installed via a Trojan or other methods on the targeted computers, converting the devices into bots.
The collective bots form a zombie network.
Botnets are primarily set up in two ways: the client-server model, and the peer-to-peer model.
The conventional way of setting up a botnet is to use the client-server model, in which bots receive their instructions and updates from a single location, typically a website or shared server. Though effective in the early days, a client-server botnet is easy to stop by simply shutting down the server location.
A client-server network is controlled from a single server location.
In a peer-to-peer (P2P) model botnet infected computers communicate directly with a few others on the network, then those few are connected to a few more, and so on, until the whole system is strung together. That way, removing one or two devices isn’t a problem, because others will be able to pick up the slack. This decentralized model makes it more difficult to detect and stop botnet attacks.
Decentralized P2P networks have built-in redundancy that makes them more resilient.
Botnets can be used for various malicious purposes. But generally botnet attacks are launched for two fundamental reasons: to spread malware quickly and/or make a large number of devices perform the same task simultaneously.
These capabilities are the basis for various types of botnet attacks, including:
Botnets can be used to send massive volumes of spam emails or phishing messages to trick victims into giving away sensitive information, downloading malware, or visiting malicious websites. A large attack surface increases the chances of successful spam and phishing attacks — the more messages sent, the more potential victims.
Botnets are often used to rapidly spread viruses or malware to as many machines as possible. A botnet allows viruses to reach the maximum number of victims in a short time frame, particularly if it’s trying to infect devices through email or an open network.
A distributed denial-of-service (DDoS) attack floods a targeted website with bot traffic, effectively shutting down the site for legitimate visitors as it slows to a crawl or crashes. Hackers often use DDoS attacks as a form of protest or to troll. The more bots involved, the harder it is to stop a DDoS attack.
A brute force attack repeatedly tries different combinations of characters and numbers to crack passwords and gain access to private accounts. This process requires a large amount of computing power, so botnets employ all their bots and pool their resources until they finally gain entry. Strong passwords are harder to crack but could be “brute-forced” with a botnet.
Cryptojacking forces botnet zombies to mine for Bitcoin and other cryptocurrencies, consuming significant device resources in the process. By using the bots to mine, cryptojackers make a profit — and victims are left with slow load times, high electricity bills, and more wear-and-tear on their devices.
Many websites rely on high amounts of traffic to profit from advertising revenue. More website traffic results in more ad impressions, which leads to more ad money for website owners. Profiteering hackers can use botnets to direct bots to their own websites, artificially inflating views and boosting ad revenue.
Hackers strive to keep devices in a botnet without detection. It’s not always obvious when your device has been turned into a bot, but there are some warning signs:
Slow performance: Botnet bots are often made to perform tasks that drain system resources, like CPU, random access memory (RAM), and system bandwidth.
Spam emails: Your contacts may be receiving spam emails from you. Botnets use personal emails to send spam and scam emails since they circumvent anti-spam measures.
High energy bills: Because botnet tasks are often high-intensity and energy-draining, you may be stuck with high energy bills.
Being a known target: By virtue of being in a botnet, your device will be labeled an easy target for other attacks, including spam, adware, and malicious pop-ups. The same hacker that’s turned your machine into a zombie knows you’re not nearly as protected as others.
A blocked antivirus: Sometimes the malware that converted your device into a bot will prevent you from downloading or running antivirus software. This leaves you vulnerable to additional malware and online threats. If you don’t have a strong antivirus on your device, download AVG AntiVirus FREE now.
Because of their versatility, there are a variety of known botnet types, each with its own characteristics and payload. Since first discovered, botnets have been responsible for a series of infamous cybersecurity attacks, wreaking havoc on an array of devices and users.
Here are some known botnet examples:
First discovered in 2011, GameOver ZeuS was a peer-to-peer botnet used to steal banking credentials, login credentials, and other sensitive information from infected devices. GameOver ZeuS worked by inserting malicious code into web browsers, modifying the web traffic, and capturing the sensitive data entered into banking websites or other online services.
On top of stealing data, GameOver ZeuS also distributed other malware, like ransomware and spam bots to expand its damage potential.
Discovered in 2016, Mirai is a botnet that targets Internet of Things (IoT) devices, like routers, cameras, and smart appliances. It scans the internet for vulnerable IoT devices that can be used in DDoS attacks and attempts to log in using weak or default credentials. Mirai is now mutating into even more powerful IoT botnet variants like Reaper.
ZeroAccess is Trojan malware that targets Windows operating systems. It emerged around 2011 and uses rootkit methods to avoid detection while forcing other devices to join the botnet. It’s primarily used for cryptojacking and fraudulent ad clicking. While ZeroAccess still exists, its scope and threat have been significantly reduced.
Emotet is a particularly dangerous botnet that can be used to steal private information from devices, or for spamming and delivering malware. It was shut down in early 2021 but it returned at the beginning of 2023 and has been gradually expanding ever since.
Using enhanced cybersecurity best practices can help you avoid infection. Here’s how to boost security against botnets and help protect your device in the event of an attack:
Use strong passwords: Some botnet infections revolve around cracking weak passwords to gain unauthorized access to devices or accounts. Complex, strong passwords are your best bet to avoid this pitfall. Remember to change the default password on devices like routers.
Use multi-factor authentication: Two-factor authentication (2FA) and multi-factor authentication (MFA) provide an extra layer of security, even if your password is stolen. Set this up on any account you can so that login attempts are validated with an extra step or two, like a PIN code sent to your phone.
Look out for phishing attacks: Botnet hackers can use phishing attacks to steal your personal details or install malware on your device. Learn the tricks to avoid spam, including stopping spam emails, and make sure you know how to spot social engineering plots. The very basics are don’t download files or click links you don’t trust, and always be careful before you click an online ad.
Install holistic security software: Security software with a wide range of tools working together in real time can help you avoid online threats like malware, suspicious websites, and malicious links.
Stay one step ahead of botnet herders and other hackers with AVG AntiVirus FREE. Shielded behind six layers of powerful malware protection and equipped with advanced features that can detect fake websites and malicious links, you’ll get award-winning, real-time protection against the range of online threats. Download it free today.
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