This is being done by changing the settings on these routers with the attackers using flaws in the router firmware to gain access, according to reports from security firms Ixia and Bad Packets Report, with the latter indicating that the redirected traffic was, at least in one wave of these hijackings, being sent to a crime-friendly hosting provider and to a service that monetises parked domain names.
Researcher Troy Mursch of Bad Packets Report, said in a blog post that all the exploit attempts had originated from hosts who were using the Google Cloud Platform. Three waves of these attacks had been noticed, he said - the first which began on 29 December last year, the second from 6 February and the third from 26 March onwards.
Mursch noted that the first wave targeted the D-Link DSL-2640B, D-Link DSL-2740R, D-Link DSL-2780B and D-Link DSL-526B routers and the IP address of the rogue DNS server used in the attack was 126.96.36.199, hosted by OVH Canada.
The latest wave had come from three Google Cloud Platform hosts and took aim at rather unfamiliar routers: ARG-W4 ADSL, DSLink 260E, Secutech, and TOTOLINK. Of the third wave, Mursch said: "The rogue DNS servers used in this round, 188.8.131.52 and 184.108.40.206, are both hosted in Russia by Inoventica Services. Internet access is provided by their subsidiary Garant-Park-Internet."
He listed the following router models and the numbers being targeted:
- D-Link DSL-2640B – 14,327
- D-Link DSL-2740R – 379
- D-Link DSL-2780B – 0
- D-Link DSL-526B – 7
- ARG-W4 ADSL routers – 0
- DSLink 260E routers – 7
- Secutech routers – 17
- TOTOLINK routers – 2265
Ixia's Mihai Vasilescu said the attacks were intended to to modify DNS settings in the routers to point to unauthorised webpages that skim user input data.
"When end users try to access a targeted website, they will land on a webpage designed to look like the original, but [that] is controlled by the attacker," he added.
Vasilescu said Ixia had noticed a fourth wave of similar attacks, beginning on 5 April. "The attackers seem to have three types of targets they are going after. Global Internet-based enterprises, local hosting providers and last, but not least, financial intuitions based in Brazil," he said.
These were: Internet-based global enterprises: paypal.com, gmail.com, uber.com and netflix.com.
Local web hosting providers: hostgator.com.br, kinghost.com.br, uolhost.uol.com.br and locaweb.com.br.
Brazilian banks and financial institutions: caixa.gov.br, itau.com.br, bb.com.br, sicredi.com.br, cetelem.com.br, bancobrasil.com.br, santander.com.br, pagseguro.uol.com.br and santandernet.com.br.
Vasilescu noted that the attacks seemed to have been crafted in a hurry. "...some of the targets aren’t even fully functional yet, which indicates either the attackers haven’t had the time to configure their servers, which is unlikely, considering that the latest DNS change attacks occurred just two days ago (3 April), or that the attackers simply misconfigured the Apache configuration," he said.
He commented: "It's 2019 and the Internet is still a dangerous place. However, simple precautions can mitigate many of the risks we face online. Making sure that our devices—in this case routers—are up-to-date and not exposing the admin interface online is important.
"Also, be extra careful when accessing important websites, banking especially. Make sure that the connections are HTTPS, check the certificate. All of this is important to make sure that when you're entering your credentials, they don't get to someone else."
A Google Cloud spokesperson told iTWire: "We have suspended the fraudulent accounts in question and are working through established protocols to identify any new ones that emerge.
"We have processes in place to detect and remove accounts that violate our terms of service and acceptable use policy, and we take action on accounts when we detect abuse, including suspending the accounts in question. These incidents highlight the importance of practicing good security hygiene, including patching router firmware once a fix becomes available.”