Quasar RAT Malware (Remote Access Tool) Open-source Project

Written by Daniel Zimmerman

Quasar RAT, short for “Remote Access Trojan,” is a potent and malicious software tool used by cybercriminals to gain unauthorized access and control over compromised computer systems. Operating under the cloak of a legitimate remote administration program, Quasar RAT employs a stealthy approach to infiltrate systems, remaining undetected by users and security measures. Originally discovered in 2015, Quasar RAT is written in the .NET programming language and has gained notoriety for its versatility, open-source nature, and advanced functionalities.

The core architecture of Quasar RAT comprises two essential components: the server-side and the client-side. The server-side boasts a user-friendly graphical interface that empowers attackers to manage connections with the client-side applications, enabling them to orchestrate and manipulate infected machines remotely. The client-side, often unknowingly downloaded by victims through deceptive means like email attachments, acts as the conduit for granting malicious operators control over the victim’s system.

Quasar RAT’s arsenal of capabilities includes remote file manipulation, alteration of system registries, monitoring and recording victim actions, and establishing covert remote desktop connections. This trojan’s silent execution capability ensures it can run discreetly in the background, remaining active for extended periods to facilitate data theft and provide attackers with persistent control over compromised systems.

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Overview of the Quasar RAT

The Origins and Evolution

Quasar RAT emerged onto the cybersecurity scene in 2015, catching the attention of researchers for its unique attributes and advanced functionalities. Built using the .NET programming language, Quasar RAT was initially speculated to be an in-house development, but further investigation revealed it to be an evolution of an older malware named xRAT. Its open-source nature, available on GitHub, contributed to its widespread use and adaptability by malicious actors.

Key Components and Architecture

At its core, Quasar RAT comprises two main components: the server-side and the client-side. The server-side boasts a user-friendly graphical interface that facilitates the management of connections with the client-side programs. This architecture also enables the creation of customized malware samples for delivery to potential victims. It’s essential to note that Quasar RAT seamlessly runs on various Windows operating system versions.

Sinister Functionalities

Quasar RAT’s appeal to cybercriminals lies in its wide array of malicious functionalities. From remote file manipulation and registry alterations to recording victim actions and establishing remote desktop connections, this RAT provides attackers with a robust toolkit for infiltrating and controlling compromised systems. The data, along with user-agent strings, is transmitted to the host server, allowing attackers to discreetly operate under the radar.

Stealthy Execution

What sets Quasar RAT apart is its ability to execute silently on infected machines. Once the victim unknowingly downloads and launches the Quasar client, the malware can remain active for extended periods, facilitating data theft and granting the attacker unprecedented control. The RAT’s presence can be elusive, with only astute users detecting its activities through the Windows Task Manager or similar applications.

Attribution and Deception

Despite extensive research, the identities behind Quasar RAT’s inception remain shrouded in mystery. The GitHub page author’s pseudonym, “quasar”, offers limited insight into the original creators. This cloak of anonymity adds to the challenges of tracing and attributing attacks back to specific threat actors.

NameQuasar RAT
DetectionTrojan:MSIL/Quasar.MAAI!MTB, Backdoor.Quasar, Trojan.Win32.Quasar, Backdoor:MSIL/Quasar.GG!MTB, Trojan:Win64/Quasar!MTB, Backdoor.Quasar.Generic, MSIL:Quasar-A [Rat], Trojan:Win32/QuasarRAT.DH!MTB, Backdoor:Win32/QuasarRAT.A, Trojan:MSIL/QuasarRAT.I!MTB
DamageQuasar RAT allows cybercriminals to access and manipulate various system functions, steal sensitive information, execute files, and perform malicious activities on compromised computers.
Fix ToolSee If Your System Has Been Affected by Quasar Virus

Quasar possesses a wide range of capabilities that can pose serious problems. It grants cybercriminals access to Task Manager, Registry Editor, file and startup item management, file download/upload and execution, system information access, execution of various computer commands, keystroke logging, password theft, and access to stored files on the compromised computer.

By employing Quasar, cybercriminals can access Task Manager to start or terminate processes and add programs that automatically run during system startup. It is essential to note that these added programs are often malicious. Furthermore, Quasar facilitates the download and execution of various files.

As a result, cybercriminals can infect computers with high-risk malware such as ransomware, trojans, or other malicious software. Quasar can function as a keylogger, recording keystrokes to steal credentials from personal and important accounts, including Facebook, email, and banking accounts, among others.

Through unauthorized access to these accounts, cybercriminals can generate revenue through transactions, purchases, and the acquisition of sensitive information. However, recorded keystrokes can lead to severe consequences such as financial loss, exposure of private information, or compromise of important accounts.

Moreover, Quasar allows cybercriminals to shut down or restart the system, potentially resulting in data loss and other related issues. Unsaved data in documents and other files could be lost as a consequence. Additionally, this RAT can steal and recover passwords from popular browsers like Google Chrome, Mozilla Firefox, and various FTP clients.

Furthermore, Quasar grants access to the Registry Editor, enabling cybercriminals to modify system and application settings. It is important to note that registry errors can trigger numerous problems, including irreversible damage to the operating system.

In summary, Quasar encompasses a multitude of functions that, if employed for malicious purposes, can lead to severe repercussions. Therefore, it is imperative to uninstall this software immediately. It is worth noting that this applies exclusively to users who were deceived into installing the program by cybercriminals.

Examples of Remote Access Trojans (RATs)

Additional instances of RATs include LimeRAT, Borat, and VenomSoftX. These tools are frequently employed to carry out illegal actions, such as stealing sensitive information and compromising accounts. Users whose computers have been infected with RATs often experience financial loss, data breaches, infections with other malware, and other detrimental consequences upon detection or discovery on their operating systems.

How did Quasar infiltrate my computer?

Research indicates that cybercriminals proliferate Quasar through spam campaigns and various downloaders or other questionable download channels. Cybercriminals employing spam campaigns send emails containing attachments, hoping that recipients will open them. If opened, these malicious attachments install unwanted and malicious software.

Common examples of files used to propagate malware include Microsoft Office documents, PDF files, executables, JavaScript files, and archives such as ZIP and RAR, which may contain malicious files. Furthermore, dubious download channels or third-party downloaders can be utilized to disseminate malware.

Typically, these sources include various unofficial downloaders or installers, unofficial websites, free file hosting websites, freeware download pages, Peer-to-Peer networks like torrent clients and eMule, and similar platforms. Opening files downloaded from these sources often leads to the installation of malicious software.

These uploaded files are disguised to appear harmless and legitimate. Other methods employed to trick individuals into installing rogue programs involve fake update tools, trojans, and unofficial software “activation” tools. Fake update tools masquerade as legitimate software updaters but instead initiate the download and installation of other malicious programs.

These tools can exploit vulnerabilities in outdated software to infect computers. Trojans, on the other hand, are malicious programs that, once installed, download, install, and propagate malware. However, they can only be effective if they are initially installed on the system. Unofficial “activators” are utilized by individuals who wish to evade payment for licensed software, but these tools frequently disseminate malicious software.

How to avoid the installation of malware?

When encountering irrelevant emails sent from suspicious or unknown addresses with attachments, exercise caution. Attachments from such emails should not be opened. It is essential to download all software exclusively from official sources, avoiding other channels and tools.

Properly update installed software using the functions or tools provided by official software developers. If activation is required for installed software, do not bypass it using third-party activation or “cracking” tools. These tools are illegal and often employed to proliferate and install malicious software.

To safeguard the operating system, regularly scan it with a reputable antivirus or antispyware suite. If you suspect that your computer is already infected, we recommend running a scan with Gridinsoft Anti-Malware to automatically remove any infiltrated malware.

How to remove the Quasar from my PC?

Quasar malware is incredibly hard to erase manually. It puts its documents in numerous places throughout the disk, and can recover itself from one of the elements. Additionally, numerous modifications in the windows registry, networking setups and also Group Policies are really hard to find and revert to the initial. It is much better to utilize a specific tool – exactly, an anti-malware program. GridinSoft Anti-Malware will fit the most ideal for malware removal purposes.

Why GridinSoft Anti-Malware? It is pretty light-weight and has its databases updated almost every hour. Furthermore, it does not have such problems and exposures as Microsoft Defender does. The combination of these details makes GridinSoft Anti-Malware perfect for eliminating malware of any type.

  • Download and install GridinSoft Anti-Malware. After the installation, you will be offered to perform the Standard Scan. Approve this action.
  • Quasar in the scan

  • Standard scan checks the logical disk where the system files are stored, together with the files of programs you have already installed. The scan lasts up to 6 minutes.
  • Quasar in the scan results

  • When the scan is over, you may choose the action for each detected virus. For all files of Quasar the default option is “Delete”. Press “Apply” to finish the malware removal.
  • Quasar - After Cleaning

Frequently Asked Questions (FAQ)

What is Quasar RAT?

Quasar RAT (Remote Access Trojan) is a tool used by cybercriminals to gain remote control over computers.

How does Quasar RAT work?

Quasar RAT allows cybercriminals to access and manipulate various system functions, steal sensitive information, execute files, and perform malicious activities on compromised computers.

Can Quasar RAT be used for legitimate purposes?

Yes, Quasar RAT is a legitimate tool with legitimate uses, such as remote administration of computers. However, it is often exploited by cybercriminals for malicious intent.

What can cybercriminals do with Quasar RAT?

With Quasar RAT, cybercriminals can access and control Task Manager, Registry Editor, download/upload and execute files, log keystrokes, steal passwords, and gain unauthorized access to personal and important accounts.

How can Quasar RAT be installed on a computer?

Quasar RAT can be installed through various means, including spam campaigns, malicious email attachments, fake update tools, trojans, unofficial software “activation” tools, and dubious download sources.

What are the risks of Quasar RAT infection?

The risks of Quasar RAT infection include unauthorized access to personal and financial information, loss of data, compromise of important accounts, installation of additional malware, and potential damage to the computer system.

How can I protect myself from Quasar RAT?

To protect yourself from Quasar RAT, avoid opening suspicious email attachments, download software only from official sources, keep your software up to date, use reputable antivirus software, and exercise caution when browsing and downloading files from the internet.

How do I remove Quasar RAT from my computer?

If you suspect Quasar RAT is installed on your computer, it is crucial to immediately uninstall the software using reputable antivirus or anti-malware tools and seek professional assistance if needed.

Is Quasar RAT illegal?

Quasar RAT itself is a legitimate tool, but its usage for unauthorized access, data theft, and malicious activities is illegal. Cybercriminals exploit Quasar RAT for illegal purposes, making it a threat to computer security.

What should I do if I believe my computer is infected with Quasar RAT?

If you suspect your computer is infected with Quasar RAT, take immediate action by disconnecting from the internet, scanning your system with reputable antivirus software, and seeking professional help to remove the malware and mitigate potential damage.

Defending Against Quasar RAT

  1. Education: Raise awareness among users about the dangers of downloading and executing files from untrusted sources, particularly email attachments.
  2. Endpoint Protection: Implement robust endpoint security solutions equipped with advanced threat detection capabilities to identify and neutralize Quasar RAT and similar threats.
  3. Network Monitoring: Employ network monitoring tools to identify unusual communication patterns between machines and external servers, which could indicate RAT activity.
  4. Regular Updates and Patches: Ensure all software, operating systems, and applications are up to date to minimize vulnerabilities that RATs often exploit.
  5. Behavioral Analysis: Implement behavioral analysis techniques to identify suspicious activities and anomalies indicative of RAT activity.
How to Remove Quasar RAT?

Name: Quasar

Description: The Quasar tool enables users to remotely control other computers across a network. These software programs, known as remote access tools (RATs), can be both legitimate and illegal. While Quasar itself is a legitimate tool, it is unfortunately often exploited by cybercriminals for malicious purposes.

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Operating System: Windows

Application Category: Malware

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About the author

Daniel Zimmerman

I'm Daniel, a seasoned professional deeply passionate about the realm of security and malware defense. With over a decade of experience in the security industry and a background in writing, I am thrilled to share my expertise through this cybersecurity blog.

Throughout my career, I've had the privilege of working on the front lines of cybersecurity, tirelessly combating emerging threats and safeguarding digital environments. This hands-on experience has allowed me to develop a deep understanding of the ever-evolving landscape of malware and cyber-attacks.

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