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PowerGhost Trojan and Cryptocurrency Miner

PowerGhost is a file-less multipurpose trojan written in PowerShell. It has been observed targeting both server and desktop devices to mine cryptocurrency, steal data and perform distributed denial-of-service (DDoS) attacks.
Threat ID:
CC-2553
Category:
Worm, Trojan
Threat Severity:
Medium
Threat Vector:
Insecure network
Published:
31 July 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This content has been archived

This article no longer conforms to NHS Digital's standards for cyber alerts, and may contain outdated or inaccurate information.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

PowerGhost is a file-less multipurpose trojan written in PowerShell. It has been observed targeting both server and desktop devices to mine cryptocurrency, steal data and perform distributed denial-of-service (DDoS) attacks.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

  • Microsoft Windows - All versions

Threat details

The initial PowerShell script is delivered via remote administration tools such as Windows Management Instrumentation (WMI) and Remote Desktop Protocol (RDP), or by a number of exploits. This heavily obfuscated script will then download the XMRig mining module, two libraries required for it to function (msvcp120.dll and msvcr120.dll), the Mimikatz password stealer, a reflective Portable Executable (PE) injector and an EternalBlue shellcode exploit.

Once executed, PowerGhost will contact a command and control server to verify that it is the latest version available and update itself if it is not. It will attempt to propagate across the network using both credentials obtained by Mimikatz and the EternalBlue exploit, before attempting to escalate its privileges. Persistence is maintained by creating a WMI class, containing all PowerGhost modules, that is activated every 90 minutes. The miner is then executed using the PE injection module.

Some variants of PowerGhost will also download a DDoS module although attacks using this module appear to be small in scale, indicating this module is still being tested.

For further information:

Remediation steps

Type Step

The EternalBlue vulnerability was fully addressed in Microsoft's MS17-010 security bulletin. Users should install this on their affected systems immediately if they have not done so already.

If Remote Desktop Protocol (RDP) is not used, then ensure port 3389 (TCP/UDP) is blocked at your internet firewall. If RDP is used, then:

  • Only allow access for authorised RDP users.
  • Enforce strong password policies.
  • Enforce multi-factor authentication.
  • Don't allow RDP access for privileged user accounts.
  • Don’t use generic accounts.
  • Set user accounts with an expiry date.
  • Audit user accounts periodically.
  • Only allow point-to-point connections from specific IP addresses where feasible.
  • Ensure Transport Layer Security (TLS) is up-to-date.
  • Log and monitor all RDP activity and investigate unusual behaviour.
  • Consider only allowing RDP for authorised virtual private network (VPN) connections.

Additionally, 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.
  • 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 12:52 pm