Deutsche Telekom says up to 900,000 customers hit with suspected cyberattack

Hundreds of thousands of Deutsche Telekom customers in Germany have been knocked offline in what the leading telecommunications provider has described as a suspected cyberattack. The firm said roughly 900,000 of its 20 million fixed-line customers have faced issues.

The connectivity problems reportedly started on Sunday 27 November when users across the country started to complain their phone and internet services were offline. Deutsche Telekom said that "specific routers" were impacted but did not reveal further details.

"Some customers are experiencing temporary problems or very marked fluctuations in quality, but there are also customers for whom the service is not working at all," the firm said in a statement published on the homepage of its website.

"We cannot exclude the possibility that the routers have been targeted by external parties with the result that they can no longer register on the network." An investigation, it added, was now being conducted to find out exactly what happened.

Deutsche Telekom said on 28 November its efforts to fix the problems were working, explaining that by midday (GMT) there was a "clear improvement in the current situation." A spokesperson said the number of customers impacted declined to about 400,000.

According to Allestoerungen.de, a website that uses statistics from DownDetector, customers' network services started to go offline at about 2pm (GMT) on Sunday however continued to persist throughout the day for users across Berlin, Munich, Frankfurt and more.

Reuters, citing several government sources, said German security officials were openly talking about the involvement of cybercriminals. "It obviously looks like the work of hackers", noted one insider.

According to Deutsche Telekom, the majority of its customers will still be able to use the fixed-line network without issue. Additionally, government spokesman Steffen Seibert said official computers were not affected by the apparent hack.

"What this incident shows is how important and right the attention is that the German government, especially the Interior Ministry, have put on exactly this topic of cybersecurity and securing our infrastructure in the digital realm," Seibert said.

In an updated statement, the telecommunications firm said a software update is now being pushed out to "all affected customers" in order to fix "the router problem."

"The software rollout already started and we can see the success of this measure," it said. "Customers should unplug their router for 30 seconds. Afterwards when reactivating the router the new software will be installed automatically from the servers."

While Deutsche Telekom claimed most of its customer-base was unaffected, Reuters reported some customers have said it may simply be unaware of the full extent of the outages. One customer on Facebook noted: "Most of the customers can't report their complaints because the Telekom hotline and online customer centre are not reachable."

This is a developing story.