Botnets & DDoS: How IoT Devices Get Weaponized

Although breached IoT devices can let threat actors move deeper into compromised home networks, they also serve a darker purpose: being weaponized in botnet attacks.

What is a botnet?

As its name suggests, a botnet is a network of internet-connected (IoT) devices used to run automation programs, conveniently referred to as “bots.”

Botnets are typically used in distributed denial-of-service (DDoS) attacks. However, their malicious potential extends far beyond DDoS campaigns, as threat actors can also use them for data theft, credential stuffing, spam campaigns, device hijacking, or diverting traffic to obfuscate illegal activity.

Perpetrators usually control the botnet using specialized command and control (C2) software.

With botnets, processing power is the name of the game, so it’s safe to say that a botnet’s destructive potential is proportional to its size; in other words, the larger a botnet is, the more damage it can do.

Beyond using infected systems to launch ruthless attacks, a botnet operator's scope is to expand its network of zombified devices, adding to its computation power.

Anatomy of a botnet

Understanding how botnets operate and why the weaponization of your IoT devices puts you at risk is crucial.

A botnet consists of multiple IoT devices hijacked by threat actors and interconnected for malicious purposes. Devices such as smartphones, laptops and computers, as well as smart TVs, sensors, smart plugs, automation hubs, thermostats, smart speakers and smart refrigerators can be compromised via malware and added to the rogue network.

Once inside a botnet, all control is usually ceded to the attacker, who can access an overview of the entire array, monitor each device individually, and send commands through a dedicated C2 center.

Botnet controllers generally employ various communication standards, including Telnet, IRC, peer-to-peer (P2P), dedicated domains, Tor hidden services, instant messaging protocols and even popular website callbacks to communicate with zombified devices.

Many “traditional” botnets use centralized C2 infrastructures. However, these structures are becoming obsolete, as modern iterations increasingly turn to P2P architectures. Decentralization helps threat actors evade takedown efforts by security professionals and law enforcement.

Botnet infection cycle

The lifecycle of a botnet starts with a systemic, insidious infection cycle:

The initial compromise – Attackers exploit vulnerabilities or use deceitful tactics to breach a device’s security.
Malicious payload delivery – After gaining access to a device, threat actors deploy malicious payloads. Typically, the payload is stealthy to avoid detection.
Achieving persistence – Perpetrators employ techniques like modifying registry entries or rootkits to achieve persistence on compromised devices, making the removal of dropped malware more difficult.
Joining the botnet – Once the above steps are taken, the infected device is connected to the botnet’s C2 server, where it lies dormant, awaiting further instructions. Perpetrators can mobilize the device at any moment for coordinated attacks.

How IoT devices become botnet “cannon fodder”

Exploitation of IoT devices is increasingly common in today’s cyber threat landscape. IoT devices, while revolutionizing concepts like connectivity and convenience, often pave the way to significant security shortcomings.

Inherent vulnerabilities

Many IoT devices are designed with cost and usability in mind rather than robust security. Common IoT vulnerabilities include:

Insecure default configurations: Many devices ship with default credentials that never change. Enforcing manual configuration (i.e., changing the default credentials) after the initial setup would solve this issue.
Lack of patch management: Firmware updates are either non-existent or infrequent, exposing devices to attacks exploiting known vulnerabilities.
Weak authentication mechanisms: Many IoT devices rely on simple passwords or no password at all, significantly lowering the barrier for compromise. Additional security mechanisms like multi-factor authentication (MFA) could help address this situation.

Common attack vectors

Threat actors typically employ several methods to breach IoT devices and add them to bot networks, including:

Brute-force attacks: Perpetrators use automated scripts that try common default passwords or use dictionaries (word lists) against a device until they breach it and gain access.
Exploiting firmware vulnerabilities: Threat actors exploit known security flaws in device firmware, often using exploit kits that increase convenience by automating the process.
Social engineering: Although not as frequently, attackers may try to manipulate users into revealing sensitive information or downloading malicious software they may use to gain access to IoT devices.

The sheer number of IoT devices worldwide creates a vast pool of billions of exploitable targets. Even small percentages of compromised devices can spawn a large botnet. The global dispersion of devices complicates efforts to identify and mitigate botnet-related threats, making them particularly dangerous.

The DDoS connection: from botnet to coordinated attacks

DDoS campaigns are one of the most visible and disruptive consequences of botnets. In a DDoS attack scenario, botnets are used to overwhelm targets with traffic, whether a website, a network, or a specific device, rendering it inaccessible or unusable.

How DDoS attacks work

In a typical DDoS attack, threat actors direct a massive volume of requests at a target, be it a single device, a server, a network, or a website. This overwhelming traffic exhausts the target’s computation resources, causing it to either slow down significantly or crash altogether.

Since the malicious traffic originates from thousands or even millions of compromised devices from around the world, tracking or filtering out malicious requests becomes a daunting task.

Why botnets are perfect for DDoS

Threat actors prefer using botnets to launch high-profile DDoS attacks against their targets for several reasons, including:

Large scale: Weaponizing a large number of infected devices allows threat actors to deliver immense volumes of traffic to their targets.
Geographic spread: The global dispersion of botnet nodes makes it daunting to trace or block traffic based solely on regions or IP addresses.
Anonymity: Using compromised devices obfuscates the DDoS attack’s origin, complicating legal actions and attack attribution.

Types of DDoS attacks

Although the principle stays the same (i.e., delivering massive volumes of traffic to targets to debilitate them), there are certain variations of DDoS attacks, including:

Volumetric attacks: In this scenario, perpetrators aim to saturate the target's bandwidth using techniques like ICMP or UDP floods.
Protocol attacks: Exploiting network protocol weaknesses such as SYN floods allows threat actors to disrupt their targets’ ability to manage connections.
Application-layer attacks: Threat actors target specific application features, such as HTTP GET/POST requests to overwhelm the application’s server.

Examples of high-profile IoT-based botnets

Several high-profile botnets could be used to shine a light on the dangers of weaponizing IoT devices in malicious campaigns, including:

Mirai: Arguably the most infamous example, the Mirai botnet exploited default credentials on IoT devices to spawn a massive botnet used to launch some of the biggest DDoS attacks ever recorded.
Mozi and Hajime: These botnet derivatives introduced new tactics including P2P C2 communication and advanced obfuscation techniques, making it more daunting for experts to disrupt their operations.

Botnets and DDoS impact on businesses and individuals

Although threat actors generally use botnets against high-profile targets, their implications are far-reaching and often affect individuals as well. These effects include:

Financial losses: Organizations often suffer substantial financial damage due to lost revenue, downtime, and costs associated with restoring systems and legal actions.
Data compromise: Sometimes botnets can be used to deploy additional malware, such as info-stealers that can exfiltrate sensitive information.
Reputational harm: Businesses that fall prey to botnet-led attacks may experience lasting damage to their reputation, eroding market value and customer trust.
Identity theft: Threat actors could launch ruthless botnet-powered attacks impacting Individuals, leading to identity theft and compromised personal data.
Compromised devices: Botnet attacks can impact individuals by using their devices for malicious purposes.

Mitigation, defensive strategies, and best practices

IoT manufacturers can adopt secure-by-design philosophies when assembling and configuring their products, ensuring that their devices have robust authentication protocols, timely, automatic updates, and extensive security audits.

Businesses and consumers are advised to take proactive measures to thwart threat actors from weaponizing their IoT devices, including changing default settings, network segmentation, and implementing rigorous monitoring and intrusion detection systems.

Early detection can help system administrators identify unusual traffic patterns or unauthorized access attempts. Furthermore, quickly isolating vulnerable or compromised devices can prevent malware from spreading further on a network.

Dedicated software can also give you the upper hand by securing devices on a network against data thieves and online threats.

Conclusion

Weaponizing IoT devices into vast, highly-destructive botnets capable of launching devastating attacks is among the most pressing cybersecurity challenges.

Understanding botnet mechanics can help you better assess the threat and identify appropriate defenses.

A mixture of proactive security measures, understanding botnet mechanics and an awareness of the vulnerabilities of IoT devices can help mitigate risks associated with IoT device weaponization in botnet attacks.

Frequently Asked Questions about botnets and DDoS

· What is a DDoS botnet?

A DDoS botnet is a network of compromised IoT devices used to overwhelm targets such as websites, servers or networks with excessive traffic, rendering them inaccessible.

· What is an example of a botnet?

One of the most infamous examples is Mirai, a botnet that weaponized devices through default credential exploitation, then used zombified devices to launch high-profile DDoS attacks.