Story image

MikroTik routers in NZ may be at risk of cryptomining - Symantec

20 Aug 18

Symantec has been tracking a large-scale coin mining campaign has currently infected about 157,000 MikroTik routers.

Cryptocurrency coinminers are the new ransomware and malicious actors have already pounced on the opportunity to make their fortune.

The coin mining was discovered in August and initially concentrated in Brazil.

However, it soon began infecting routers around the world, and MikroTik routers are available in New Zealand.

Mitigation

MikroTik has already published a patch to address CVE-2018-14847.

Symantec recommends users to install the patch on their routers if they have not done so already.

Users can also consider disabling the following services on their routers, if not required:

  • TELNET
  • SSH
  • FTP
  • WINBOX

These routers are used by many organisations and businesses, including internet service providers.

While MikroTik was prompt in patching CVE-2018-14847, unfortunately, poor patching practices by vendors and users mean that there are plenty of vulnerable routers still out there.

A router post-mortem

At the outset, the compromised router has multiple services running on it.

Interestingly, the infected router had the default web service disabled.

Pointing a browser to the infected router’s port 80 causes it to serve the Coinhive script responsible for coin mining.

But when the infected router is found in between a client sending a request and a server receiving it, this HTML page is only served when there’s an error.

This is because internally the router is configured with a firewall rule that helps serve this malicious HTML page.

Using network address translation (NAT), the firewall rule takes traffic bound to port 80 and redirects it to port 8080.

The router is also configured to run a default proxy server on port 8080 that’s responsible for serving the Coinhive script.

The script below is responsible for performing multiple malicious actions on the router including, but not limited to:

  • Enabling the proxy service
  • Adding the firewall NAT entry
  • Enabling Winbox, FTP, SSH services
  • Disabling the WWW service
  • Scheduling various tasks to remain persistent on the router
  • Adding a backdoor user with the name “ftu” to the FTP group

It’s likely that this script was downloaded using the inbuilt /tool fetch command and run using the /import command.

All the infected MikroTik routers (v6.29 to v6.42) that the Symantec Threat Intelligence encountered were running the Winbox service, which is known to be vulnerable to CVE-2018-14847.

When exploited successfully, this flaw can allow an attacker to bypass authentication and compromise the router.

After the router is compromised, the hackers can load their malicious error page, which is displayed any time a user accessing the internet via the router encounters an HTTP error.

Every time the error page is displayed, the victim is unknowingly mining Monero (XMR) for the hackers.

Disruption in the supply chain: Why IT resilience is a collective responsibility
"A truly resilient organisation will invest in building strong relationships while the sun shines so they can draw on goodwill when it rains."
Verifi takes spot in Deloitte Asia Pacific Fast 500
"An increasing amount of companies captured by New Zealand’s Anti-Money laundering legislation are realising that an electronic identity verification solution can streamline their customer onboarding."
Businesses too slow on attack detection – CrowdStrike
The 2018 CrowdStrike Services Cyber Intrusion Casebook reveals IR strategies, lessons learned, and trends derived from more than 200 cases.
What disaster recovery will look like in 2019
“With nearly half of all businesses experiencing an unrecoverable data event in the last three years, current backup solutions are no longer fit for purpose."
Proofpoint launches feature to identify most targeted users
“One of the largest security industry misconceptions is that most cyberattacks target top executives and management.”
McAfee named Leader in Magic Quadrant an eighth time
The company has been once again named as a Leader in the Gartner Magic Quadrant for Security Information and Event Management.
Symantec and Fortinet partner for integration
The partnership will deliver essential security controls across endpoint, network, and cloud environments.
Is Supermicro innocent? 3rd party test finds no malicious hardware
One of the larger scandals within IT circles took place this year with Bloomberg firing shots at Supermicro - now Supermicro is firing back.