New worm can infect home modem/routers

It is suspected that the botnet originated in Australia as the first activity from the botnet was detected here. Australian IT consultant Terry Baume first observed it infecting a Netcomm NB5 modem/router. You can read his full analysis here.

The botnet binary was further analysed by members of the website DroneBL (a real-time
IP tracker that scans for and botnets and vulnerable machines) which came to the conclusion that the “psyb0t” or “Network Bluepill” botnet was mostly
a test run to prove the technology. After the botnet’s discovery and public outing the botnet operator swiftly shut it down.

The first generation targeted very
few models of router though the current most recently discovered generation (dubbed ‘version 18’ in the code) targets a
wide range of devices.

The malware contains the shellcode for
over 30 different Linksys models 10 Netgear models and a variety of other
cable and DSL modems (15 different shellcodes).

A list of 6000
usernames and 13000 passwords were also included to be used for brute force entry to Telnet and SSH logins which are open
to the LAN and sometimes even the public WAN side of the routers. Generally
routers do not lock a user out after a number of incorrect password
attempts making brute force attacks possible.

According to DroneBL any router that uses a MIPS processor and runs the Linux Mipsel operating system (a simple operating system for MIPS Processors) is vulnerable if they have the router administration
interface or sshd/telnetd in a DMZ with weak
username/passwords. DroneBL noted this includes devices flashed with the open-source firmwares openwrt and dd-wrt and the group also said that other routers may be vulnerable as it had observed the bot running on routers based on the Vxworks operating system.

Of course exploiting home network devices is more useful than infecting PCs because they are mostly running 24 hours a day unlike PCs. The attack of a router additionally enables hackers and exploiters to exploit a network with greater levels of stealth as there’s no change to PCs on a network except perhaps reduced network performance.

The staff of DroneBL noted that the exploit is very difficult to detect as the only way to discover it is to monitor traffic going in and out of the router itself and that’s beyond the reach of software running on a computer. In the past exploits on professional-grade Cisco routers were easier to detect as Cisco provides dedicated ports for connecting to the router monitoring internal performance and configuring them. However the vast majority of home routers sacrifice these features for the sake of cost savings.

According to DroneBL the botnet is capable of scanning for vulnerable PHPMyAdmin and MySQL installations. It can also disable access to the control interfaces of a router meaning a factory reset will be necessary to clear the worm.

DroneBL attempted to shut down the Command & Control channel that the botnet utilized and was successful. The DNS which was hosted with was also nullrouted. The Command & Control is now defunct but at the height of its penetration the botnet was suspected to control 100000 hosts. The author of the botnet chatting anonymously on an IRC channel claimed to have infected 80000 routers at one point.

APC is making enquiries with router manufacturers for their assessment on which of their models is vulnerable and what users should do to protect themselves.

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With additional reporting by Dan Warne.