The Mirai Botnet is one of the most recognized cyber threats, known for taking control of vulnerable IoT devices to carry out large-scale DDoS attacks. Its legacy continues to influence modern botnets, including the recent Gorilla Botnet, which uses similar tactics with advanced capabilities to exploit IoT vulnerabilities on a larger scale.
In this article, we will explore how Mirai works, its impact and how organizations can stay protected.
What is a Mirai Botnet?
The Mirai Botnet is a form of malware that targets IoT devices, such as routers, cameras, and other connected gadgets, turning them into a network of infected devices. This botnet is then used to launch massive DDoS attacks, bombarding websites, servers, and networks with traffic, causing them to become unreachable for legitimate users.
First discovered in 2016, the Mirai Botnet gained attention for its ability to exploit weak or default security settings in IoT devices. It has since been used in several high-profile attacks, disrupting critical internet infrastructure and setting a precedent for similar botnets that followed.
How the Mirai Botnet Operates
Mirai operates by scanning the internet for unsecured IoT devices. These devices typically come with default usernames and passwords that users fail to change. Once Mirai finds these vulnerable devices, it infects them and adds them to the botnet. The botnet can then launch DDoS attacks by flooding servers with excessive traffic, rendering the targeted websites and services unavailable to legitimate users.
Additionally, Mirai employs reflection and amplification techniques to enhance the attack. Reflection involves sending traffic from infected devices to a third-party server, which then reflects the traffic back to the target, concealing the source. Amplification exploits vulnerabilities in protocols like DNS and NTP, allowing the botnet to generate much larger traffic volumes than it initially sends, making the attack more powerful.
These techniques, combined with the botnet’s widespread reach, make it difficult to contain and lead to severe disruptions.
Attack Techniques of the Mirai Botnet
The Mirai Botnet uses various attack techniques, each designed to flood networks with harmful traffic and disrupt services. These attacks can target different parts of an infrastructure, overwhelming systems and causing significant downtime. Below are the key types of attacks employed by Mirai:
- UDP Flood: Mirai sends many UDP packets to a target port, which overwhelms the server. This makes the server unable to respond to real user requests, causing slowdowns or complete outages.
- SYN Flood Attack: Mirai sends incomplete connection requests, using up the server’s resources. This prevents the server from making proper connections, causing it to crash or become unresponsive.
- DNS Query Flood: This attack targets DNS servers by flooding them with excessive traffic. As a result, the server can’t resolve domain names properly, making websites or services unavailable to users.
- HTTP Flood: Mirai sends many HTTP requests to web servers, causing the servers to become overloaded. This type of attack results in website downtime and prevents users from accessing the site.
- GRE Flood: Mirai uses GRE packets to spoof the source IP address, sending a huge amount of data. This overwhelms networks and causes connectivity problems, disrupting service.
The Evolving Threat: Mirai’s Variants
Since its discovery, Mirai has continuously evolved, with its creators developing new variants to exploit emerging vulnerabilities and enhance its capabilities. This evolution has led to several notable incidents, each showcasing the growing sophistication of the botnet:
- OVH Hosting Attack (September 2016): One of the largest DDoS attacks in history targeted French hosting provider OVH. The attack reached over 1 Tbps and used more than 145,000 compromised IoT devices, demonstrating the immense power of the Mirai botnet.
- Krebs on Security Attack (September 2016): Cybersecurity journalist Brian Krebs experienced a massive 620 Gbps DDoS attack on his website. The attack forced his hosting provider to stop supporting him, showing how Mirai can overwhelm even strong defences.
- Dyn DNS Attack (October 2016): Mirai targeted DNS provider Dyn with multiple coordinated attacks, causing widespread disruptions in internet services across the U.S. and Europe. Popular platforms like Twitter, Spotify, and Reddit were offline, highlighting the botnet’s ability to disrupt essential services.
- Deutsche Telekom Router Incident (November 2016): An attempt to recruit over 900,000 routers into the Mirai botnet disrupted internet services for users of Deutsche Telekom in Germany. Although the recruitment failed, it caused significant outages, reflecting the global reach of the botnet.
- Liberia’s Internet Blackout (November 2016): The botnet effectively crippled Liberia’s internet services through repeated DDoS attacks. The country’s reliance on limited infrastructure made it particularly vulnerable, leaving it offline for extended periods.
- Pandora Variant Attack (September 2023): In a more recent attack, a new variant of Mirai, named “Pandora,” targeted inexpensive Android-based smart TVs and TV boxes. This variant leveraged these devices to launch DDoS attacks, revealing the botnet’s continued evolution and exploitation of emerging vulnerabilities in consumer technology.
- Corona Variant: A more recent evolution, the “Corona” variant, utilizes zero-day vulnerabilities in IoT devices, allowing it to infiltrate and exploit systems previously thought secure.
Impact of Mirai Botnet Attacks
The widespread effects of Mirai botnet attacks are far-reaching. Businesses relying heavily on online platforms have faced significant disruptions. For example, during the Dyn DNS attack, popular websites such as Twitter and Spotify were inaccessible for hours, causing loss of user engagement and revenue for companies depending on their services.
The consequences are not limited to immediate revenue loss. Prolonged service outages create logistical challenges, requiring businesses to invest heavily in recovery efforts. For instance, companies like OVH Hosting endured one of the largest DDoS attacks ever recorded, impacting their ability to maintain service to clients.
Additionally, the reputational damage from these attacks can linger long after the disruption has been resolved. Businesses seen as vulnerable to cyber threats risk losing customer trust, making it harder to retain and acquire new customers. As IoT devices proliferate, the ongoing risk of Mirai-like attacks highlights the critical need for businesses to prioritize IoT security to prevent both financial and reputational damage.
How to Mitigate the Mirai Botnet
Along with addressing security weaknesses in your IoT devices and their usage, it’s crucial to adopt best practices and technologies to safeguard your network against Mirai botnet attacks. Key recommendations include:
Secure Device Credentials: Always change the default usernames and passwords on your IoT devices. Use strong, unique credentials to make it difficult for attackers to gain access.
Regular Firmware Updates: Ensure your IoT devices are always updated with the latest security patches. Firmware updates often contain fixes for known vulnerabilities, helping protect against exploits.
Network Segmentation: Isolate IoT devices from critical network segments. This ensures that if one device is compromised, it won’t give attackers easy access to other systems on the same network.
Monitor for Unusual Traffic: Use network monitoring tools to identify unusual traffic patterns that could indicate a potential botnet infection. Early detection can help prevent large-scale attacks.
Implement DDoS Protection Software: Use DDoS protection solutions to filter malicious traffic before it reaches your network and to mitigate large-scale attacks.
How Does AppTrana Defend Against the Mirai Botnet?
AppTrana WAAP provides robust defence against DDoS attacks carried out by Mirai and other botnets. It protects websites and APIs from DDoS threats by using a combination of real-time traffic filtering, bot detection, rate limiting, and behaviour analysis. By controlling the rate of requests, it prevents the server from being overwhelmed.
AppTrana also uses advanced bot detection techniques to stop botnet attacks. It analyses traffic patterns and identifies bots based on behaviours such as rapid request rates or abnormal access attempts. Once a bot is detected, AppTrana can apply various mitigation strategies, including CAPTCHA challenges, JavaScript challenges, or blocking malicious IPs, to stop the attack from affecting the application.
Finally, AppTrana WAAP continuously monitors traffic for anomalies, with machine learning helping to identify and respond to new attack patterns in real-time. By using a multi-layered approach to both DDoS and bot protection, AppTrana ensures that your applications stay protected, even during the most aggressive attacks, keeping them secure and operational without interruption.
