Worldwide Botnets

Botnets, networks of compromised computers controlled by a malicious actor, are a persistent threat in the cybersecurity landscape. These digital armies can cause significant damage, from disrupting online services to facilitating massive fraud schemes. Here are nine of the most destructive botnets ever unleashed:

1. 911 S5: Dismantled in May 2024, this botnet infected over 19 million devices globally and is considered one of the largest ever. Its operators used it for massive financial fraud, identity theft, and other crimes, causing an estimated $5.9 billion loss in fraudulent pandemic unemployment claims alone.

2. Mirai: Known for exploiting vulnerable Internet of Things (IoT) devices like routers and cameras, Mirai powered massive Distributed Denial of Service (DDoS) attacks, including one that disrupted access to major websites like Twitter and Netflix in 2016.

3. Zeus (Zbot): This malware, active from 2007-2010, specialized in stealing banking information, leading to massive financial losses worldwide. Variants like Gameover ZeuS further enhanced its capabilities.

4. Emotet: Described as "the world's most dangerous malware" by Europol, Emotet is a sophisticated botnet that has delivered various malicious payloads like ransomware and banking Trojans. It spreads primarily through malicious email attachments and can propagate within networks.

5. Conficker: This highly virulent worm, active in the 2000s and still present today, infected millions of computers and compromised military, manufacturing, and healthcare systems. It was notable for its persistence and caused significant disruption.

6. SoBig.F: This worm, active in 2003, caused widespread disruption, including bringing down freight and computer traffic in Washington D.C and affecting Air Canada. It spread rapidly through email and caused an estimated $37.1 billion in damages.

7. Mydoom: One of the fastest-spreading worms in history, Mydoom (2004) was primarily used for DDoS attacks and sent out millions of spam emails daily. Its creator remains unknown.

8. Srizbi: While active for only about a year (2007/08), the Srizbi botnet was responsible for a staggering 60% of all spam worldwide, sending out billions of emails every day. Its takedown in 2008 caused a 75% drop in global spam volume.

9. Mariposa: This botnet, active from 2009-2011, controlled over 12 million machines and was used for data theft and banking fraud. Its takedown in 2009 resulted from successful efforts by researchers and law enforcement agencies.

These are just a few examples of the numerous botnets that have wreaked havoc across the globe. Their existence underscores the importance of strong cybersecurity measures, vigilant awareness, and international cooperation to combat these ever-evolving threats.