VBShower Backdoor

VBShower is a newly observed PowerShell-based polymorphic backdoor, created by the Inception advanced persistent threat group to replace their older PowerShower malware.

Threat ID:: CC-3177
Category:: Backdoor
Threat Severity:: Medium
Threat Vector:: Backdoor, Spear phishing
Published:: 15 August 2019 12:00 AM

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Summary

VBShower is a newly observed PowerShell-based polymorphic backdoor, created by the Inception advanced persistent threat group to replace their older PowerShower malware.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

As with PowerShower, Inception delivers VBShower using an embedded HTA file distributed via targeted spam or spear-phishing campaigns. When opened, this file will execute an unnamed launcher, which in turn executes VBShower. The HTA file also contains a context file which is used by VBShower to connect to a command control (C2) server.

Once installed, VBShower will download VBS files containing the intended payloads from the C2 server, which are then installed on the affected system. In some campaigns, VBShower will also install PowerShower, which is then used to extract user credentials and files.

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.

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: 11 January 2022 9:20 am