VPNFilter malware is shedloads worse than expected
VPNFilter malware is shedloads worse than expected by
Oh those Russians
It looks like a Russian hack of US routers is shedloads more dangerous than thought.
Two weeks ago, officials in the private and public sectors warned that hackers working for the Russian government infected more than 500,000 consumer-grade routers in 54 countries with malware that could be used for a range of nefarious purposes.
That would be bad enough, but researchers from Cisco’s Talos security team say additional analysis shows that the malware is more powerful than originally thought and runs on a much broader base of models, many from previously unaffected manufacturers.
Dubbed VPNFilter the routers can conduct a man-in-the-middle attack on incoming Web traffic. Attackers can use a ssler module to inject malicious payloads into traffic as it passes through an infected router. The payloads can be tailored to exploit specific devices connected to the infected network. Pronounced “essler”, the module can also be used to surreptitiously modify content delivered by websites.
Cisco’s new analysis shows that VPNFilter poses a more potent threat and targets more devices than was reported two weeks ago.
Craig Williams, a senior technology leader and global outreach manager at Talos said initially he thought the hack was made for offensive capabilities like routing attacks around the internet.
“But it appears [attackers] have completely evolved past that, and now not only does it allow them to do that, but they can manipulate everything going through the compromised device. They can modify your bank account balance so that it looks normal while at the same time they’re siphoning off money and potentially PGP keys and things like that. They can manipulate everything going in and out of the device.”
Talos said VPNFilter targets a much larger number of devices than previously thought, including those made by ASUS, D-Link, Huawei, Ubiquiti, UPVEL, and ZTE. The malware also works on new models from manufacturers previously known to be targeted, including Linksys, MikroTik, Netgear, and TP-Link. Williams estimated that the additional models put 200,000 additional routers worldwide at risk of being infected.
“They’re looking for very specific things. They’re not trying to gather as much traffic as they can. They’re after certain very small things like credentials and passwords. We don’t have a lot of intel on that other than it seems incredibly targeted and incredibly sophisticated. We’re still trying to figure out who they were using that on.”
Wednesday’s report also details a self-destroy module that can be delivered to any infected device that currently lacks that capability. When executed it first removes all traces of VPNFilter from the device and then runs the command “rm -rf /*,” which deletes the remainder of the file system. The module then reboots the device.
The botnet still remains active, thanks to the piecemeal design of the malware. Stage 1 acts as a backdoor and is one of the few known pieces of router malware that can survive a reboot. Meanwhile, stages 2 and 3, which provide advanced functions for things such as man-in-the-middle attacks and self-destruction capabilities, have to be reinstalled each time an infected device is restarted.
To accommodate for this limitation, stage 1 relies on a sophisticated mechanism to locate servers where stage 2 and stage 3 payloads were available. The primary method involved downloading images stored on Photobucket.com and extracting an IP address from six integer values used for GPS latitude and longitude stored in the EXIF field of the image. When Photobucket removed those images, VPNFilter used a backup method that relied on a server located at ToKnowAll.com.
Even with the FBI’s seizure of ToKnowAll.com, devices infected by stage 1 can still be put into a listening mode that allows attackers to use specific trigger packets that manually install later VPNFilter stages. That means hundreds of thousands of devices likely remain infected with stage 1, and possibly stages 2 and 3.
Router owners should always change default passwords and, whenever feasible, disable remote administration. For extra security, people can always run routers behind a proper security firewall. Williams said he has seen no evidence VPNFilter has infected devices running Tomato, Merlin WRT, and DD-WRT firmware, but that he can’t rule out that possibility.