Router-Based Botnet On The Loose

Now your routers can become zombies, too: Researchers have discovered a botnet that uses home DSL devices to build out its army.

The so-called "psyb0t" malware may be the first such code to go after home network devices, say researchers at DroneBL, an organization that monitors abuse of infected machines. So far, somewhere around 100,000 devices have been infected, are being used to wage distributed denial-of-service (DDoS) attacks, and are stealing usernames and passwords, according to DroneBL.

DroneBL first discovered the botnet after it hit the site with a DDoS attack. The botnet is IRC-based and had been studied earlier this year by another researcher, Terry Baume, who wrote a white paper (PDF) detailing how vulnerabilities in embedded Linux devices, such as Netcomm's NB5 ADSL modem, were being infected and recruited into a botnet.

Routers traditionally have been considered relatively immune to malware and attacks, and botnets traditionally use PCs and servers. "Malware is starting to use routers -- in this case, still simple Linux boxes," says Felix "FX" Lindner, a researcher with Recurity Labs, who recently demonstrated how Cisco-router hacking isn't as difficult as once thought.

To be at risk of psyb0t infection, DroneBL researchers say a router must be Mipsel-Linux-based; have telnet, SSH, or Web-based interfaces available to the wide-area network; and have a weak username and password, or firmware daemons that are exploitable. "As such, 90 percent of the routers and modems participating in this botnet are participating due to user error (the user themselves or otherwise)," the researchers blogged.

The router-based botnet is stealthy. "Most end users will not know their network has been hacked, or that their router is exploited. This means that in the future, this could be an attack vector for the theft of personally identifying information. This technique will certainly not be going away," the researchers wrote.

Have a comment on this story? Please click "Discuss" below. If you'd like to contact Dark Reading's editors directly, send us a message