Quasar RAT

Quasar is a very popular RAT in the world thanks to its code being available in the open-source. This malware can be used to remotely control the victim’s computer.

Type
Trojan
Origin
Unknown
First seen
1 January, 2015
Last seen
30 September, 2020
Global rank
15
Week rank
11
Month rank
9
IOCs
3179

What is Quasar RAT?

Quasar is a remote access trojan is used by the attackers to take remote control of infected machines. It is written using the .NET programming language and available to a wide public as an open-source project, making it a popular RAT that was featured in a number of attacks.

General description of Quasar RAT

Quasar RAT was first discovered in 2015 by security researchers, who, at the time, speculated that this RAT was written by an in-house development team after performing the analysis of a sample. Quasar is an evolution of an older malware called xRAT and some of its samples can carry out as much as 16 malicious actions.

Over the course of its lifetime, the malware has been updated several times, improving its overall functionality. The last version of the malware which was developed by the original author is v. 1.3.0.0. It was released in 2016. Since that time several third parties have adapted the RAT and issued their own version, both minor and major with the last major version being v. 2.0.0.1.

The RAT we are reviewing today consists of two main components – the server-side component and the client-side component. The server is equipped with a graphical user interface and it is used for managing connections with the client-side programs. The server-side component is also utilized to build malware samples which are eventually delivered to potential victims. Malware user has an option to select attributes and customize the executable to fit the needs of the attacker.

The functionality of the resulting malware includes remote file management on the infected machine, registry alterations, recording the actions of the victim, establishing remote desktop connections and more.

It should be noted that Quasar execution can unfold completely silently, thus, once the victim downloads and launches the client, usually delivered in a document via email, it can stay active for a long period of time, stealing data and giving the hacker control over the infected PC. The malware does generate a process that can be discovered using the Windows Task Manager or a similar application, but active user actions are required to discover Quasar trojan presence on a machine.

As far as creators of this malware are concerned, the group of people or a person behind the original version of this malware managed to remain anonymous. The little known information that we do have does not go beyond the name of the GitHub page author which states simply “quasar”.

As evident from the description on the “official” Quasar GitHub page, this malware is presented as a legitimate remote administration program, which is clearly misleading. In fact, Quasar was featured in an attack aimed at the US government early in 2017. Later the same year another wave of attacks using this malware occurred, this time targeting the private sector.

Quasar RAT malware analysis

The execution process of this malware can be viewed in a video recorded in the ANY.RUN malware hunting service, allowing to take a look at how the contamination process unfolds.

process graph of the quasar stealer execution Figure 1: Displays the lifecycle of Quasar in a visual form, as shown on the graph generated by ANY.RUN.

text report of quasar analysis Figure 2: Shows a customizable text report generated by the ANY.RUN malware hunting service.

Quasar RAT execution process

Quasar execution is pretty straightforward but can vary in minor details from sample to sample. In a given example, Quasar was dropped from a Microsoft Office file. The dropped file changed the registry value to make itself run with every operating system start, checked for external IP and also copied itself at another location. After all these steps, the malware started the main malicious activity - collecting information about the operating system and waiting for commands from the C2 server.

How to avoid infection by Quasar?

Quasar trojan writes itself into scheduled tasks and uses registry keys to achieve persistence, allowing the malware the run every time a machine is started. The persistence method is chosen based on user privileges. As such, if the user has admin rights, the malware uses schtasks to create a scheduled task which launches after a user logs on with the highest run level. If admin rights are lacking, then the scheduled task can only go as far as to add a registry value which is configured in the client builder and added to the current path as the startup program.

Distribution of Quasar RAT

Just as most of the other RATs, Quasar is distributed in email spam campaigns that carry the malware’s loader. The loader is embedded in a malicious file attachment which usually carries a name designed to trick the user into thinking that he or she is receiving some sort of a document. Sometimes these files will have a double extension such as docx.exe. This is done to trick the victim into thinking that the attached file is harmless. Of course, once opened, such files start a command prompt rather than Microsoft Office.

How to detect Quasar RAT using ANY.RUN?

ANY.RUN uses Suricata IDS rule sets so if malware trying to communicate with C&C servers it will be detected. To look at what threats were detected just click on the "Threats" section of the "Network" tab.

quasar network threats Figure 3: Quasar network threats

Conclusion

Quasar trojan is a powerful open-source malware equipped with a robust persistence mechanism and a complete feature set of malicious capabilities. Being available to anybody with programming knowledge, Quasar became a widely used RAT which was even featured in an attack targeted at the American government.

However, unlike other more advanced Trojans, Quasar RAT does not have extremely sophisticated anti-analysis features, which makes setting up robust cyber-defense an easier task, especially when using malware hunting services like ANY.RUN to simplify and streamline the research process.

IOCs

IP addresses
208.95.112.1
79.134.225.83
193.161.193.99
66.254.114.41
3.13.191.225
208.91.197.91
3.134.125.175
79.134.225.95
79.134.225.11
172.67.75.176
3.127.138.57
79.134.225.5
104.31.138.11
104.31.139.11
52.14.18.129
58.158.177.102
3.124.142.205
79.134.225.74
208.95.112.1
54.75.82.184
Hashes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2.tcp.ngrok.io
majul.com
smtp.recornit.com
smtp.maizinternational.com
smtp.telenor-com.xyz
smtp.pdcblt.net
smtp.raymond-john.com
smtp.ametexegypts.info
smtp.nutritionauctores.com
smtp.radiologyauctores.com
smtp.gastroenterologyauctoresonline.org
smtp.sleepauctoresonline.org
smtp.fortvelle.com
cthree.msoftupdates.com
ctwo.msoftupdates.com
cone.msoftupdates.com
elx01.knas.systems
eceda.duckdns.org
scca.duckdns.org
work1234.duckdns.org

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