What is a Botnet ❓ Definition, Types, Example Attack

Professionals, who make system security arrangements, are well-aware of the term ‘botnet’. Often used for the chain of hijacked computers/systems, the term ‘botnet’ should be well understood if a restorative and robust system is instructed as their wrong usage can lead to tremendous chaos.

Botnet Definition

By literal definition, botnet refers to the web of blighted or hijacked computers used for processes like sending spam emails, distributing malware, and framing DDoS attacks. Activation of botnet doesn’t mandate the permission of the device owner.

Alone, botnets are not detrimental to the network and can be used for crucial tasks like chatroom management and tracking the points accumulated during online games. The controlling party of the botnet is known as a bot-herder and each individual machine, concerned in the network, is known as a bot.

The earlier key purpose of assembling a botnet is to make monotonous tasks easier than ever. The best example of this chatroom management wherein it handles the job of eliminating people who are violating the policies. Botnets keep track of language used during the chats, which is otherwise a too taxing job for humans.

However, some clever minds figure out other its ill-usage, by utilizing its ability of seamless code execution inside another system. Because of these features, hackers or attackers were succeeded in using for password theft and tracking the keystrokes made on a specific device.

How Does a Botnet Work?

There are multiple stages in this process. Botnets, when used in full capacity, can perform attacks at a large scale. Hackers need to support botnets with supplementary machinery or devices to enhance the ability of a botnet. To have a deeper understanding of botnets modus operandi, one must understand the key terminologies.

Bot herder is what is required to lead the connected corrupted devices in the network. It’s functional via remote commands and guides the devices to perform certain actions.

Bot or zombie computer is the term used for the infected system/device used in the creation of a botnet. The bots are mindless devices and behave as instructed or guided by the bot herder’s command.

Stages of botnet building

The next step to figure out the functionality of botnet is knowing the building process. The procedure involves three steps:

  1. Stage 1 — Prepare and Expose

At this stage, the bad actor figures out the vulnerability to introduce into the user’s device.

The vulnerability hunting takes place in the website, human behavior, and application. By doing so, the hacker prepares a set-up to lure the target to get exposed to malware, knowingly or unknowingly.

Most commonly, hackers figure out the vulnerabilities in websites and the software.

Additionally, malware is delivered via emails or random messages.

2‍. Stage 2 — Infecting the user via malware

The next action that the botnet performs is activating the malware so that the end-user is infected and has compromised security. The process of infecting the device usually takes place via the Trojan virus or social engineering method.

Some attackers adopt a more hostile approach and deploy drive-by-download techniques to infect the device. Using all these methods, attackers corrupt the targeted device with botnet malware.

3. ‍Stage 3 — Controlling the targeted devices

The last stage of botnet working methodology is gaining control over each device. Hackers systematize the involved infected machines in the botnet and design a methodology to manage them remotely. In general, around thousands of devices are controlled in the process via a huge zombie network. Once the stage is successfully completed, the bad actor is able to gain admin-like access to the targeted devices or computers.

The fruitful activation of the botnet allowed hackers to read or write the data stored in the system, capture any personal information, share the data from targeted devices, keep an eye on all the activities happening on the targeted device, and search other hidden vulnerabilities.

Types of Botnet Attacks

  • DDoS

DDoS or Distributed Denial-of-service attack involves disturbing the customary traffic of a server in a way that actual or intended audiences are not able to access the website. The attack gains its efficacy from using the assorted corrupted systems as the sources of creating disturbing traffic. The corrupted devices involved could be computers, PC, IoT devices, and many other data-driven devices.

From another angle, a DDoS attack can look like a traffic jam created intentionally so that desired end-users don’t reach their destinations.

  • Phishing

One of the most common botnet attacks, phishing involves representing bad actors or hackers as reliable sources to lure victims to share crucial information like passwords and banking credentials. Using these details, bad actors can steal data and money. The attack is accomplished by multiple means like email phishing, vishing, and smishing. Phishing attack targeting a huge audience is often performed via spear and whale phishing

  • Brute Force Attacks

Causing more than 5% of total security breaches, brute force attack is based on guessing. The threat actor keeps on guessing the user credentials till the time s/he gets the right credentials and gains unwanted access to the targeted system. The Hit and Trial methodology work here. It’s a simple process with a better success rate. There are some brute force attack tools used for the task as well.

Botnet control models

To ensure the effective functioning of the botnet and complete the intended aim, attackers need to control the botnet continuously. Usually, two models are used for this task.

Model #1- Centralized or The client-server model

The centralized botnets utilize this model’s basic network infrastructure to establish the communication network with the devices facing the attack. It’s highly functional as command and control servers generate robust communication.

However, as these servers can be spotted easily and can be deactivated effortlessly, bot herder won’t be communicative with the bots once the C&C server is down or hacked.

Model #2- Decentralized or The peer-to-peer model

An advanced model, this model involves establishing communication while involving all nodes or peers connected in this network. In this type of botnet controlling model, all infected nodes are commanded to communicate in the network without asking for a particular and dedicated C&C server (or authentication).

Botnets following the P2P model are stronger as compared to botnets functional via the client-to-server model. Also, they are not easy to be disturbed. This advantage has made the P2P model more popular these days.

Examples of a Botnet

  • Mirai Botnet Attack

You might have heard of it. After all, Mirai is one of the most powerful botnets until today.

First noticed in 2016, this botnet attack impacted many Linux-based webcams and routers under a high-end DDoS attack. The attack infected the machines used for scanning the internet consumed by IoT devices. Users, who didn’t change the default passwords, we targeted in this attack.

Things become worse when the original code of Mirai was published online and gave other hackers an opportunity to create more powerful malware by modifying it accordingly.

  • Zeus Botnet Attack

The attack happened in 2007 and is one of the most notorious attacks happened in history. It was first designed to fetch the end-users banking details using spam or phishing emails.

The attack involved the use of a Trojan horse program in infecting the devices. Since its inception, its multiple variants have been presented. CrytoLockerransomware is an example of this. As per the estimation of Damballa in 2009, the botnet infected 3.6 million hosts.

What Are Botnets Used For?

Based upon the intention of the attackers, botnets can be used widely to fulfill money or data theft-related aims. The most common usage of botnets is as quoted below.

  • Fraudulent or money stealing

Attacks can use a botnet to steal money directly or indirectly. Phishing emails or creating a false website for banks are key methods to accomplish this goal. They can translate the payment or transaction details and use them to steal money.

  • Data theft

User data has huge worth in the market and hackers they the help of botnets to steal individual data or break into the database of an enterprise. They later sell user data to third parties and earn money. Such botnets remain dormant and steal personal information.

  • Cryptocurrency mining

Cryptocurrency has gained huge popularity and attackers can mine cryptocurrency with the help of botnets. The process is known as cryptojacking.

  • Perform spamming and phishing frauds

Using botnets, bad actors can launch email spamming and phishing scams at large as they can disperse the infected emails to millions of targets in one go. There are specially designed spam botnets for this job.

Regardless of the method used, the motives are the same, stealing money or data. However, some attackers can use botnets just because they can. They use botnets to display their capabilities and prove their excellence to the world. We have witnessed many security breaches when bad actors steal enterprise data and expose it on the dark web for free.

How to Track Botnets?

The early detection of botnets plays a crucial role in hazard management as it will keep the damage as less as possible. However, tracking the presence of botnet is a demanding task as this malware doesn’t consume noticeable processing power. This makes it difficult to figure out whether or not a botnet is present on your system.

Still, there are certain ways that can make this job done:

  • Consider the presence of botnet in your device if you witness an abrupt spike in bandwidth consumption and a sudden dip in the internet speed. Whenever a botnet is active, it consumes bandwidth to send spam emails or perform a DDoS attack. This results in excess bandwidth consumption and a significant drop in speed.
  • The presence of a botnet will also lead to unwanted or unexpected changes in the system files. If you’re feeling that a certain account’s configuration or file’s access preference has altered without any intervention then it’s because of a botnet.
  • Botnets will force a particular program to run as long as a malware attack is performed. So, if you’re facing any issues in closing a particular program then botnet could be a reason for this.
  • The presence of botnets will infect the system’s OS and will create a hindrance in an OS update.
  • If you’re noticing any unidentified processes in the task manager refers to the botnet presence.
  • One can easily track botnet with the help of anti-virus software. They can scan the presence of botnets and much other malware easily and effortlessly. Some high-end anti-virus software even comes with a special botnet checker.

How to Protect Your Computer from Botnets?

Botnet attacks can be too damaging, if not handled properly. The below-mentioned ways can keep botnet attacks at bay.

  • Updated OS

Make sure the used system features updated software. With each software update, users are granted enhanced security patches that can deal with known vulnerabilities. It’s an easier way to stay out of the reach of botnet malware.

  • Download from trusted resources

The most common way to introduce a botnet attack is to lure the target. Enhanced security seekers must download the attachments coming from untrusted or unknown sources. For professional communications, it’s better to make PDFs password-protected so that they don’t serve as a botnet attack mean.

  • No accessibility to suspicious links

Just like attachments from unknown sources are trouble-makers, strange links can be a phishing attack. So, don’t entertain any strange link.

  • Paying attention to website security

Websites having no security wall and robust encryption could be a hub for botnets. Learn more about the website security criteria and maintain a safe distance from shady websites.

  • Stay away from P2P downloads

P2P downloading services are very risky as they feature many malicious attachments. If possible, don’t use P2P downloads.

  • Changing login details while introducing new devices

Each time you install a new device like a webcam, router, or any IoT device, make sure you’re changing the login credentials. The use of default passwords makes botnet or IoT botnet attacks easier than ever.

  • Using the protection of firewall

Using a firewall is a sure shot way to stay safe from botnet and much other malware as it automatically blocks the insecure connection.

  • Strong password and 2FA

Using a strong password is a smart strategy to keep the odds of any kind of malware attack as little as possible. 2FA or two–factor authentication will keep botnet malware away from your devices and make it a bit safer.

  • Deployment of anti-virus software

Reliable anti-virus software will spot the presence of botnet malware in its infancy stage and will get rid of it before it can do any harm to the system.

  • Dependable security tool

Elimination of botnet with the help of a renowned security tool like Wallarm allows end-users to enhance the overall security of the system, spot the presence of botnets in the early stage, and frame a protective security strategy.

Originally published at https://www.wallarm.com.

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Ivan Novikov

CEO at Wallarm. Application security platform to prevent threats and discover vulnerabilities in a real-time.