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Virut Botnet

Virut is a botnet malware family that was first seen in 2006. The botnet was believed to have been mostly shut down by a Polish-led sinkhole operation in 2013.

Threat ID:
CC-2829
Category:
botnet
Threat Severity:
Medium
Threat Vector:
Exploit
Published:
5 December 2018 12:00 AM
Report a cyber attack: call 0300 303 5222 or email [email protected]

This content has been archived

This article no longer conforms to NHS Digital's standards for cyber alerts, and may contain outdated or inaccurate information. Use of this information contained in this page is at your own risk

Summary

Virut is a botnet malware family that was first seen in 2006. The botnet was believed to have been mostly shut down by a Polish-led sinkhole operation in 2013.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

Some variants have been observed evading the sinkhole and distributing additional malware in November 2018.

Virut spreads by injecting code into any executable or screensaver file that is accessed. It also injects malicious iframes into HTML, PHP and ASP files. This means that Virut can be distributed to additional devices via network shares, removable drives and malvertising. The most recent variants inject code into the winlogon.exe process.

Virut is known to utilise a domain generation algorithm and an encrypted protocol with RSA signature verification for command and control signalling. When a communication link has been established using the most recent variants, the affected device is instructed to download a portable executable file. This attempts to drop further payloads over HTTP, using the user agent 'AdInstall'.

Remediation steps

Type Step

To prevent and detect a trojan 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: 17 February 2020 12:59 pm