Hundreds of thousands of Deutsche Telekom customers in Germany faced Internet outages on Sunday and Monday following a widespread Internet of Things attack from the so-called Mirai botnet.

Deutsche Telekom on Monday said 900,000 customers suffered outages as a result of a botched router attack.

"The attack attempted to infect routers with a malware but failed, which caused crashes or restrictions for four to five percent of all routers," the company said, adding that its network was not affected.

Mirai works by taking over insecure Internet of Things devices like routers and baby cameras, harnessing them to direct gigabits of traffic to critical points in the Internet's infrastructure. In the case of the Deutsche Telekom attack, the Mirai botnet lobbed assaults against customer routers, but apparently did not succeed in turning them into bots. Following the attack, Deutsche Telekom advised affected users to unplug their routers and reboot. The company is also offering updates for affected routers.

"After the reboot, the router should function normally," Deutsche Telekom said in a statement. "The routers are back to their original state after the reboot, meaning there was no permanent infection with malware."

The Mirai botnet has been causing trouble all over the world in recent months. In October, it unleashed a massive DDoS attack that limited access to several highly trafficked Web services. Connected IoT devices from tens of millions of IP addresses worldwide flooded domain name system (DNS) provider Dyn with traffic, making sites like Twitter, Spotify, Airbnb, Netflix, Reddit, GitHub, and many others inaccessible.

The same botnet was also this month used in another attempt to take the entire country of Liberia offline.