Menu
Tens of thousands of home routers at risk with duplicate SSH keys

Tens of thousands of home routers at risk with duplicate SSH keys

The setup mistake could put the routers at risk of being compromised

Tens of thousands of home routers from Telefónica de España share the same SSH key pairs.

Tens of thousands of home routers from Telefónica de España share the same SSH key pairs.

A setup mistake has apparently left hundreds of thousands of home routers running the SSH (Secure Shell) remote access tool with identical private and public keys.

John Matherly used Shodan, a specialized search engine for querying Internet-connected devices, and found more than 250,000 devices that appear to be deployed by Telefónica de España sharing the same public SSH key.

Matherly, who founded Shodan, performed the search after someone posted a shorter version of a public key -- called a fingerprint -- for their device.

He was surprised to find more than 250,000 other devices, mostly in Spain, that shared the same public key fingerprint. It means the devices -- which are likely home routers -- also have the same private key, which could pose a security risk.

A different search found another 150,000 devices, mostly in China and Taiwan, that have the same problem.

Matherly said in a phone interview on Wednesday it is possible the manufacturers copied the same operating system image to all of the routers.

Another explanation is that an ISP reflashed the devices with custom settings, but did so insecurely, Matherly said. Newly imaged devices running SSH should be configured to generate their own unique key pairs.

But it is questionable whether SSH should be running on a home router anyway. It is used by administrators to enable encrypted, remote access to a system, but that capability isn't usually needed for home routers. All of the Telefónica de España routers were running a version of SSH called Dropbear.

"It's kind of weird that [SSH] is there in the first place," said Matherly, who also blogged about his findings. "You don't need to change your Wi-Fi password when you're away from home. It's very unusual."

The settings for a home router can usually be accessed by those on its local network through a password-protected Web interface.

Matherly said another problem of thousands of devices sharing the same key pair is that there is no way to verify a specific device. The public key fingerprint is a way to verify that a device is who it says it is, but if many devices share the fingerprint, it's impossible to tell, Matherly said.

It's hard to say if the key errors means that a remote attacker could log into all of the devices, as it would depend on how the routers are configured for remote authentication.

But "the biggest issue I see is that if you compromise one of them, you know that every other device is going to be exactly the same," Matherly said.

Matherly said he didn't take it that far and that he only queried the devices with Shodan, which goes through the motions of setting up a connection with a router, including collecting its public fingerprint, but doesn't try to login.

It would be near impossible for consumers to figure out how to generate new SSH keys or turn SSH off in the routers, Matherly said.

The problem is not unique to home routers. Cloud computing providers have occasionally made mistakes by not generating fresh SSH keys with new instances of virtual machines, Matherly said.

"This kind of issue actually happens all over the cloud," he said.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Follow Us

Join the New Zealand Reseller News newsletter!

Error: Please check your email address.

Tags Shodansecurity

Slideshows

Top 50 defining moments of the New Zealand channel in 2016

Top 50 defining moments of the New Zealand channel in 2016

Reseller News looks back on a tumultuous 12 months for the New Zealand channel, assessing the fallout from a year of sizeable industry change. Whether it be local or global mergers and acquisitions, distribution deals or job changes, the channel that started the year differs somewhat to the one set to finish it - Reseller News assesses the key moments that made 2016.​

Top 50 defining moments of the New Zealand channel in 2016
​Hewlett Packard Enterprise honours high achieving NZ channel

​Hewlett Packard Enterprise honours high achieving NZ channel

Hewlett Packard Enterprise honoured its top performing Kiwi partners at the second running of its HPE Partner Awards in New Zealand, held at a glitzy ceremony in Auckland. Recognising excellence across eight categories - from distributors to resellers - the tech giant celebrated its first year as a standalone company, following its official split from HP in 2015.

​Hewlett Packard Enterprise honours high achieving NZ channel
Nutanix treats channel partners to Christmas cruise

Nutanix treats channel partners to Christmas cruise

Nutanix recently took to the seas for a Christmas Cruise around Sydney Harbour with its Australia and New Zealand staff, customers and partners to celebrate a stellar year for the vendor. With the sun out, they were all smiles and mingled over drinks and food.

Nutanix treats channel partners to Christmas cruise
Show Comments