Botnets: The silent cyber threat

Cyberthreats are inevitable in the ever-changing digital world, growing in number and technology. The botnet is one of the most infamous and harmful weapons in the arsenal of online criminals.

A network of compromised computers and other connected devices that are under the command and control (C&C) of a centralized infrastructure is known as a botnet. This article explores the subtleties of botnets, their mode of operation, potential repercussions, and measures you can implement to fight them.

What is a Botnet?

A botnet is a network of infected computers or devices that are controlled remotely by a hacker or a group of hackers. These infected machines, also known as bots or zombies, are used to carry out various malicious activities, such as distributed denial-of-service (DDoS) attacks, phishing attacks, and data theft. Botnets can be created using various types of malware, including Trojans, viruses, and worms. Once a device is infected, it becomes part of the botnet and can be controlled by the bot herder, who can use it to carry out malicious activities.

Anatomy of a botnet

Botnet is a contraction of the words robot and network and refers to a network of computers that are connected and controlled by the “bot herder”. The bot herder can spread botnet malware incredibly fast with the use of botnets, since each bot is infected with malware - the bot herder can in theory have millions of bots around the world and thus infect all of the millions of devices.

These devices are e.g. computers, smartphones, Internet of Things (IoT) devices, and servers. Cybercriminals establish control over these devices by exploiting vulnerabilities, tricking users into installing malicious software, or leveraging default credentials.

Once infected, these devices become bots, serving as a massive army of compromised machines ready to execute the botnet operator’s commands.

The modus operandi of botnet attacks

Botnets are an attractive feature to hackers since they have many purposes. A botnet attack can be highly structured, involving stages and types such as centralized and decentralized attacks. Some of them include:

DDoS attacks: One of the most common uses of botnets is to organize Distributed Denial of Service (DDoS) attacks. By flooding a target server or network with a massive amount of bot traffic, the target becomes inaccessible to users, leading to serious disruption and financial damage. Learn more about how DDoS attacks work and their impact.
Spam distribution: Cybercriminals can use spam to spread malware, phishing schemes, and other frauds by using botnets to send out enormous numbers of spam emails.
Brute force attacks: Botnets have the ability to use stolen credentials to breach web accounts or conduct brute force attacks on login systems. These brute force attacks often involve dictionary attacks, which exploit weak user passwords to gain unauthorized access. Dive into the mechanics of brute force attacks here.
Click fraud: Botnets can be programmed to generate fake clicks on online ads, tricking the advertisers into thinking that their ad is getting genuine attention - and they thus pay money to keep it. It is, however, non-existent traffic they pay for which ultimately disrupts the advertising ecosystem.

Data theft: Botnets can be used to exfiltrate sensitive data from compromised devices, leading to potential identity theft, corporate espionage, or the exposure of private information.

Additionally, using strong passwords and enabling multi-factor authentication can help prevent bot herders from exploiting weak user passwords.

Hackers use rootkits to become an administrator of a certain software - in this case they become the admin of the botnets.

The underground economy of malicious software

It’s hard to imagine the scale of botnets since they are enormous. If a centralized server is taken down, the entire botnet can be compromised, highlighting the vulnerabilities of such a structure. And because they are so big, they have become attractive for hackers - both to make and also to rent or buy. Hackers can sell or rent out botnets on the dark web, making it a lot easier for rookie hackers to engage in cybercrime; without having to develop their own botnet infrastructure.

The prices vary depending on the size and capabilities of the botnet, providing cybercriminals with a means to monetize their illegal activities.

Cybercriminals don’t use regular payment methods, their entire economy is an underground economy with cryptocurrency and transactions, since it’s undetectable.

Explore everything about how the dark web fuels cybercrime.

Challenges in detecting and mitigating DDoS attacks

Botnets are designed to remain stealthy and circumvent detection to increase their impact. Detecting and mitigating botnets pose significant challenges due to the following factors:

Botnet resilience: Botnet operators are getting better at putting resilient infrastructures in place. They use domain generation algorithms (DGAs) to dynamically switch out C&C servers, which makes it hard for ethical hackers to track down and take down the hacker’s infrastructure.
Encrypted communication: Since many botnets use encrypted communication channels, our regular security measures might not be able to decrypt the content, thus making the detection efforts even more complicated than they already are.
Geographic distribution: Botnets are scattered around the world, meaning that there’s infected devices all around the globe. That is why it’s so difficult to track down the bot herder(s) and remove the botnet.
Monitoring network traffic: By observing traffic flow and volume, security teams can detect potential data leaks or DDoS attacks early, enhancing the organization's cybersecurity posture.

How botnets work

Botnets operate through a command and control (C&C) system to communicate with infected machines. There are two main types of botnet architectures: client-server and peer-to-peer (P2P).

Client-Server model: Infected computers connect to a central server

In a client-server model, infected computers connect to a centralized server, which acts as the command and control center. The bot herder uses this server to send commands to the infected machines, which then carry out the malicious activities. This type of architecture is easier to detect and shut down, as it relies on a single point of failure.

Peer-to-Peer (P2P) Model: Infected computers communicate with each other

In a P2P model, infected computers communicate with each other directly, without the need for a centralized server. This type of architecture is more difficult to detect and shut down, as it does not rely on a single point of failure. P2P botnets are often used for more sophisticated attacks, such as DDoS attacks and data theft.

Types of botnet attacks

Botnets can be used to carry out various types of attacks, including:

Distributed Denial-of-Service (DDoS) attacks: Overwhelm a website or network with traffic

DDoS attacks involve overwhelming a website or network with traffic from multiple infected machines. This can cause the website or network to become slow or unresponsive, making it difficult for legitimate users to access it. DDoS attacks are often used to extort money from websites or to disrupt online services.

Other types of botnet attacks include phishing attacks, data theft, and malware distribution. Phishing attacks involve using infected machines to send fake emails or messages that trick users into revealing sensitive information, such as login credentials or financial information. Data theft involves using infected machines to steal sensitive information, such as credit card numbers or personal data. Malware distribution involves using infected machines to distribute malware to other devices, which can then be used to carry out further attacks.

To protect yourself from botnet attacks, it is essential to use anti-virus software, keep your operating system and software up to date, and avoid clicking on suspicious links or opening attachments from unknown sources. Additionally, using strong passwords and enabling multi-factor authentication can help prevent bot herders from exploiting weak user passwords.

The fight against bot herders

It’s a never ending fight against botnets, but we can try and implement different strategies to our cybersecurity to make it harder for the hackers to infiltrate our software.

First and foremost, we should always keep our software updated with the latest updates - these contain patches that fix the security holes and gaps that the hackers exploit to infect user devices. Secondly, we should install antivirus software that can detect and remove cyber threats on our devices.

Next thing you should do is to have firewalls installed, and do regular check ups of your software. Firewalls secure your computer network and the activities surrounding it - so it would most likely detect unusual activities from botnets.

Lastly, awareness training is key when it comes to cybersecurity. It’s often the human errors that give hackers access to software and data - and hackers know this. They are constantly trying to exploit this vulnerability to their advantage. So, by educating yourself in cybersecurity, you strengthen your defense against hackers and decrease the risk of falling victim of a cyber attack.

Don't forget the botnets

Botnets represent a persistent and formidable challenge in the world of cybersecurity. These powerful networks of compromised devices have the potential to wreak havoc on a massive scale, affecting you, your organization, and the critical software infrastructure on your devices.

By understanding how they work and their scale, you can take proactive steps to better protect yourself from cyber attacks. The safety of your digital ecosystem relies on your vigilance.