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Nodersok Malware

Nodersok is a newly observed fileless malware targeting users across Western Europe and the USA. Also known as Novter or Divergent, it uses embedded versions of a number of legitimate applications as part of its attack chain.

Threat ID:
CC-3237
Category:
Threat Severity:
Low
Threat Vector:
Spam, Malvertising
Published:
2 October 2019 12:00 AM
Report a cyber attack: call 0300 303 5222 or email [email protected]

Summary

Nodersok is a newly observed fileless malware targeting users across Western Europe and the USA. Also known as Novter or Divergent, it uses embedded versions of a number of legitimate applications as part of its attack chain.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

  • Microsoft Windows - All versions

Threat details

Delivery of Nodersok begins with a downloaded HTA file (although it is unclear how this file is distributed, it is likely to be via spam emails or malicious adverts), which will execute embedded JavaScript code when opened. This code will download and launch a second-stage file (either JS or XSL) containing several PowerShell commands. These commands are then used to disable security and update services, install Nodersok, and escalate its privileges. Versions of the Windivert packet capture library and the Node.exe framework are also downloaded.

Once installed, Nodersok will connect to an initial command and control (C2) server to download a JavaScript-based SOCKS proxy as well as the details of a secondary C2 server. The proxy is then deployed using Node.exe, whilst Nodersok connects to the second C2 server through Windivert.

Remediation steps

Type Step

To prevent and detect an infection, ensure that:

  • A robust program of education and awareness training is delivered to users to ensure they don’t open attachments or follow links within unsolicited emails.
  • All operating systems, anti-virus and other security products are kept up-to-date.
  • Regular anti-virus and security scans are performed on your organisation’s estate.
  • All day-to-day computer activities such as email and internet are performed using non-administrative accounts.
  • Strong password policies are in place.
  • Network, proxy and firewall logs should be monitored for suspicious activity.
  • User accounts accessed from affected devices should be reset on a clean computer.
  • Your organisation adopts a holistic all-round approach to Cyber Security as advocated by the 10 Steps to Cyber Security.

Last edited: 14 February 2020 2:58 pm