PNG Dropper Downloader

First observed in August 2017, PNG Dropper (sometimes stylised as png_dropper) is a downloader trojan developed and used by the Turla advanced persistent threat group.

Threat ID:: CC-2812
Category:: Trojan
Threat Severity:: Medium
Threat Vector:: Spear phishing
Published:: 29 November 2018 12:00 AM

Report a cyber attack: call 0300 303 5222 or email [email protected]

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Summary

First observed in August 2017, PNG Dropper (sometimes stylised as png_dropper) is a downloader trojan developed and used by the Turla advanced persistent threat group.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

At the time of publication it is unclear how PNG Dropper is distributed, although Turla are known to use highly targeted spear-phishing campaigns to deliver their other tools. It is delivered disguised within the publicly available JPEGView image viewer or 7-Zip file archive utility. These tools are packaged with a series of extra PNG files containing PNG Dropper and the intended payload. When opened, these tools will compile and execute PNG Dropper.

Once installed, PNG Dropper will extract, recompile and install the payload from the remaining PNG files. Newer variants can extract encrypted portable executable files from the registry.

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: 17 February 2020 1:00 pm