In October 2016, Mirai took down Dyn, a major DNS provider, causing widespread outages across Twitter, Netflix, Reddit, and dozens of other major sites. The attack peaked at 1.2Tbps — the largest ever at that time. The weapon: compromised IP cameras, DVRs, and routers running default factory credentials.
How Mirai Worked
- Scanned the internet for devices with open Telnet ports (23, 2323).
- Tried 61 hardcoded default username/password combinations.
- Compromised devices were commandeered as bots while still functioning normally for their owners.
- Command-and-control (C2) issued attack orders: target IP, duration, attack type, packet settings.
The Open-Source Legacy
When Mirai's author released the source code publicly in September 2016, it spawned dozens of variants: Masuta, Satori, Reaper, Emotet-linked loaders, and more. Modern IoT botnets use Mirai's core scanner combined with N-day exploits to compromise devices without needing default credentials.
The Threat Today
- IoT device count is projected to exceed 30 billion by 2025.
- Firmware update mechanisms on consumer routers and cameras remain largely non-functional.
- Mirai-variant attacks are a daily occurrence — Akarguard blocks Mirai-family traffic patterns continuously.
Defense priority
If you're running internet-exposed services, assume Mirai-family bots are targeting you right now. The question is whether your infrastructure absorbs the flood or collapses under it.