What is Botnet Attack and How Does Botnet Work

A botnet attack is a targeted cyber-attack during which a collection of devices that are all connected to the internet are infiltrated and hijacked by a hacker. Referring to a robot network, a botnet attack is carried out by a nefarious actor that aims to seize control of a collection of computers, servers, and other types of networks for a series of potential malicious purposes.

What is a botnet attack?

The growth and progress of technology has changed the world in positive ways. However, such expansion brings with it increased potential for security breaches and unsavory technological activity, such as, among other things, a botnet attack. A botnet attack refers to the hijacking of a network of computer devices for the purpose of carrying out a series of disruptions and other harmful activities. Aiming to launch automated mass attacks without the consent of those in control of the devices and networks in question, a botnet attack is a potentially destructive multi-layered scheme. Typically, a botnet attack may be aimed at disrupting the activity of a network, sabotaging services, stealing valuable or private information, illegally mining other people’s cryptocurrency, or selling access to hijacked networks to other criminals with malicious intentions.

What is botnet in cyber security?

In the realm of cyber security, a botnet has the potential to target a broad variety of devices that form a much larger network. Any device that has access to the internet is at risk of a botnet attack. With the number of computer-based devices that connect to the internet increasing every day, so does the threat of cyber security breaches.

While a wide variety of devices are susceptible to becoming the victim of a botnet attack, they may be categorized for the purpose of clarity:

1. Mobile devices: Including things like smart phones, tablets, and laptops, mobile devices are used by most people, making them a common target of botnet attacks.
2. Internet of Things (IoT) devices: These days, individuals may use several different IoT devices on a regular basis, making them more vulnerable to becoming the victim of a potential botnet attack. They may include:
   • Wearable devices, including smart watches, and other types of devices that track fitness.
   • Home security devices ranging from cameras to speakers, televisions, and even thermostats.
   • In-car entertainment, including both audio and visual hardware and software.
3. Traditional computers: Whether you are using a Windows or Mac operating system, all types of traditional computers with internet access are vulnerable to a botnet attack.
4. Internet infrastructure hardware: This revolves around hardware that is used to support internet connections between other types of devices, most frequently web servers and routers.

Thus, it is no wonder that these botnets expand so quickly and often slip under the radar for an extended period of time. Indeed, any of the above devices may be part of a botnet without you even knowing it. While up-to-date anti-virus software ought to be able to detect a malicious presence, by the time this software has been run, your device may already be compromised by a botnet attack. Perpetuating the problem and emphasizing the potential risk of such an attack, individual devices may be the victim of more than one botnet attack at the same time.

How does a botnet work?

With anonymity being one of the most important attributes of a botnet attacker, remote programming is used to control targeted networks. Botnets operate within large and complex systems, meaning that having a main server is essential. Therefore, each botnet attack has its own Command-and-Control (C&C) that is responsible for distributing instructions to each of the devices that are under control - so-called “zombie” computers - which act as the central power of the system.

Commands may be provided by botnets both directly and indirectly by means of two possible models:

1. Centralized client-server models

Generally recognized as the more old-fashioned method, centralized models make use of a top-down command system, creating a kind of hierarchy of power and control with what is referred to as the “herder” or "bot herder" – the ultimate instruction giver – at the top and the “zombie” computers at the bottom, with intermediate-level “herders” finding themselves somewhere in between. While this allows for an organized method of attack, a weakness of a centralized botnet attack is that it is not difficult for the defenders of targeted systems to detect “herders” and therefore, put an end to the havoc. Thus, centralized client-server models are generally seen as being outdated and are no longer commonly used by attackers.

2. Decentralized peer-to-peer (P2P) models

Decentralized P2P models tend to operate more surreptitiously. In order to do this, all “zombie” computers are embedded with instruction responsibilities. This means that by making contact with just one lower-level “zombie” computer, commands can be spread from the “herder” to all the “zombies” within the targeted network in one fell swoop. Therefore, decentralized P2P models are far more commonly used today and are capable of causing damage quicker than previous methods are able to within a botnet attack. Thus, a botnet attack involves commands being sent throughout the network of malware-infected devices, instructing said bots to perform nefarious tasks.

What are the stages of a botnet attack?

1. Exposure

Users are exposed to malicious software by means of unknown vulnerabilities found in software or websites. Alternatively, hackers often choose to infiltrate systems by means of infected messages and emails.

2. Infection

Targeted users’ devices are then infected, either by being convinced to manually download a virus or by becoming the victim of an aggressive “drive-by download” that automatically infects the device once a specific website is visited.

3. Activation

Finally, the infected bots that make up the network are organized and malicious commands are sent out among them to begin implementing its specific purpose in the botnet attack.

What are the main purposes of a botnet attack?

The purposes of a botnet attack may range from stealing users’ private information to simply disrupting systems operations. Essentially, a botnet attack has the ability to:

1. Steal sensitive data
2. Monitor the activities of users
3. Disrupt and prevent systems from operating effectively
4. Install/run any range of applications and programs
5. Send data to and from infected machines
6. Read and write system data
7. Detect and target vulnerabilities within infected devices

This technology is also frequently used to monitor systems’ abilities to withstand malicious attacks. These are called White Hat Botnets and they aim to prevent unwanted access to devices and networks.

What are the different types of botnet attacks?

However, the total number of active bots within a network does not necessarily dictate the relative power of the botnet attack. Rather, the type of attack has far more influence on its success.

1. Brute force attack: When passwords are unknown, hackers use technology that implements a system of repetitive guessing, utilizing real-time feedback, as well as leaked personal information for password attempts.
2. Distributed Denial of Service (DDoS) attack: Targeted networks are flooded with excessive activity from spoofed IP addresses with the objective of crashing the system entirely.
3. Spam and phishing: Individuals are tricked into sharing personal data and login credentials by means of malicious emails and messages, thus providing attackers with access to the system in question.
4. Device bricking: Aiming to prevent targeted devices from operating, this type of botnet attack infects the device with malware that corrupts it and, consequently, deletes all evidence of its presence, allowing it to go undetected.

How can you avoid a botnet attack?

Just like anything unpleasant, prevention is better than a cure. Therefore, are there several possible ways in which you may be able to avoid a botnet attack:

1. Restrict access to important networks
2. Adopt cyber security hygiene best practices
3. Use tools like Sangfor Botnet Detection to enable more effective detection and scanning
4. Ensure that the device software is constantly up to date
5. Regularly change the login credentials of the default device
6. Add new devices only when necessary and properly secure them
7. Remove devices that are no longer being used or monitored
8. Train employees on cyber security awareness

However, attackers are smart and sometimes, prevention simply is not possible. If you do happen to find yourself in the unfortunate position of becoming the victim of a botnet attack, there are a few ways in which you may be able to prevent it from going any further:

• Disable the central server: This ought to be your first port of call since this is where the commands are originating from. 
• Sever connections between bots: If you are able to prevent bots from communicating with each other by means of severing the connections to control servers, you ought to be able to then scan devices for malware and reinstall software. Many tools, such as the Sangfor Anti-Bot Tool, exist to help combat issues like Botnet and malware attacks.

Depending on the strength of the botnet, these solutions may be able to disable the attack immediately. However, sophisticated hackers may be able to develop intricate webs between bots and multiple control servers, making it difficult to stop the attack entirely. However, this does not make it impossible. Ultimately, as the potential threat of botnet attacks grows with the evolution of constant advancements in technology, the most realistic way of defending devices and systems against such attacks will always be prevention and early detection. Contact Sangfor today to find out more about how we can help you prepare for botnet attacks and meet all your other cyber security needs.