What Is CCleaner Trojan.Nyetya Malware and How to Remove It

What Is CCleaner Trojan.Nyetya Malware and How to Remove It

This article aims to help you by showing how to remove the CCeaner Trojan.Nyetya virus completely from your computer and how to protect yourself in the future as well.

If you are reading this article, chances are you have CCleaner installed on your computer. News broke out recently that hackers managed to slither a backdoor into two versions of CCleaner – CCleaner 5.33.6162 and v1.07.3191 of CCleaner Cloud. The infection happened via two primary Trojan horses – the Trojan.Floxif and Trojan.Nyetya. If you have one of the following versions of CCleaner installed on your computer, we advise you to read this article in order to learn how to detect and remove the Trojan.Nyetya infection.

Threat Summary

NameCCleaner Trojan.Nyetya
TypeTrojan Horse
Short DescriptionAims to infect your computer and steal information from it or assume administrative control over it.
SymptomsRegistry entries added in multiple Windows registry sub-keys, like the “Agomo” key. Suspicious files created on your computer.
Distribution MethodVia CCleaner version 5.33.6162 and CCleaner Cloud version 1.07.3191.
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How Does Trojan.Nyetya Infect CCleaner

During their research, security experts have established that n artifact was found within the binary of the CCleaner, called CCleaner.pdb. The artifact is located in the following directory:

→ \workspace\ccleaner\branches\v5.33\bin\CCleaner\Release\CCleaner.pdb

When researchers cross referenced this with the valid certificate of the software, they have concluded that most likely a hacker compromised a segment of the development in order to create a separate environment that grants it access in order to perform the malicious operations. The way the malware installation works is when you install CCleaner itself, there is a function in it, called ‘__scrt_get_dyn_tls_init_callback’ and it calls a code execution which in turn results to the successful dropping of the payload of the CCleaner Trojan.Nyetya on the infected computer system.

CCleaner Trojan.Nyetya Analysis

Similar to the Floxif trojan, Trojan.Nyetya drops a malicious file, named CBkrdr.dll and this file may be located in the following directory:

→ C:\Program Files\Common Files\System\

After the initial malicious file has been dropped on the infected computer, the virus may modify the registry editor of the infected computer, adding a Windows registry sub-key, going by the name “Agomo”. It has the following location:

→ HKLM\SOFTWARE\Piriform\Agomo

In addition to this, the Trojan.Nyetya also connects to a remote C2 server in order to transmit data via HTTPS POST request. The connection is to the following IP address:


From there, it may execute the loader and CCleaner may appear to look normal. However, the Trojan.Nyetya profiles the system, analyses if the user is administrator and transmits data from the infected machine to the C2 server. This data may be:

  • Your keystrokes.
  • Your saved passwords on your browsers.
  • Important documents.
  • Screenshots of your desktop.
  • Network information. (IP, MAC, Next hop addresses, etc.)
  • Financial data.
  • Data from external devices (USB, SD cards, etc.)
  • Install other malware.

So far is known that there are over 5 million installations of CCleaner each week and the app is installed in all 55 languages it offers, which means that the situation has already spread on a global scale. Security experts have managed to contain the situation by upgrading the software to version 5.34, but it will take time for some users to learn about the breach and update their systems.

In addition to this, Avast, who bought the Piriform, the developers of CCleaner on July 18, have released a report in which law enforcement, Cisco and Avast have conducted their investigations on the matter and have taken down the C&C server of the malware and registered multiple domains which could have been used in the future infections of the both Trojans. This has resulted in the new patched versions which were released, called CCleaner 5.34 and CCleaner Cloud 1.07.3214. This has resulted to the number of infected user machines decreasing from ~2 million to under a million computers.

How to Remove CCleaner Trojan.Nyetya from Your Computer

In order to successfully delete this Trojan horse from your PC, manual removal may prove to be a tricky process. This is why, it is strongly advisable to follow the removal instructions below.

The best course of action according to security experts at this point is to download an advanced anti-malware software which will automatically scan for the malicious objects created and modified by this malware and delete them permanently.

Ventsislav Krastev

Ventsislav has been covering the latest malware, software and newest tech developments at SensorsTechForum for 3 years now. He started out as a network administrator. Having graduated Marketing as well, Ventsislav also has passion for discovery of new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management and then Network Administration, he found his passion within cybersecrurity and is a strong believer in basic education of every user towards online safety.

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