What is the Win32:Evo-gen [Trj] virus?
Written by Robert Bailey

What is Backdoor.Quasar infection?

In this article you will discover concerning the meaning of Backdoor.Quasar and its adverse effect on your computer system. Such ransomware are a type of malware that is clarified by on the internet frauds to require paying the ransom money by a sufferer.

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In the majority of the cases, Backdoor.Quasar ransomware will certainly advise its targets to initiate funds transfer for the purpose of reducing the effects of the modifications that the Trojan infection has introduced to the victim’s gadget.

Backdoor.Quasar Summary

These adjustments can be as complies with:

  • Executable code extraction. Cybercriminals often use binary packers to hinder the malicious code from reverse-engineered by malware analysts. A packer is a tool that compresses, encrypts, and modifies a malicious file’s format. Sometimes packers can be used for legitimate ends, for example, to protect a program against cracking or copying.
  • Creates RWX memory. There is a security trick with memory regions that allows an attacker to fill a buffer with a shellcode and then execute it. Filling a buffer with shellcode isn’t a big deal, it’s just data. The problem arises when the attacker is able to control the instruction pointer (EIP), usually by corrupting a function’s stack frame using a stack-based buffer overflow, and then changing the flow of execution by assigning this pointer to the address of the shellcode.
  • Reads data out of its own binary image. The trick that allows the malware to read data out of your computer’s memory.

    Everything you run, type, or click on your computer goes through the memory. This includes passwords, bank account numbers, emails, and other confidential information. With this vulnerability, there is the potential for a malicious program to read that data.

  • Network activity detected but not expressed in API logs. Microsoft built an API solution right into its Windows operating system it reveals network activity for all apps and programs that ran on the computer in the past 30-days. This malware hides network activity.
  • Ciphering the papers situated on the sufferer’s hard disk — so the target can no longer utilize the information;
  • Preventing normal accessibility to the target’s workstation. This is the typical behavior of a virus called locker. It blocks access to the computer until the victim pays the ransom.


One of the most common channels whereby Backdoor.Quasar Ransomware Trojans are infused are:

  • By methods of phishing emails;
  • As an effect of customer ending up on a resource that hosts a malicious software program;

As quickly as the Trojan is effectively injected, it will either cipher the information on the victim’s PC or protect against the device from functioning in a proper fashion – while likewise positioning a ransom money note that points out the need for the victims to impact the payment for the function of decrypting the files or recovering the file system back to the initial condition. In many instances, the ransom note will certainly show up when the client restarts the COMPUTER after the system has actually already been harmed.

Backdoor.Quasar distribution channels.

In various edges of the world, Backdoor.Quasar grows by jumps and bounds. However, the ransom notes as well as methods of obtaining the ransom quantity may differ depending on certain local (local) setups. The ransom money notes and tricks of obtaining the ransom quantity might differ depending on specific neighborhood (regional) setups.

Ransomware injection

As an example:

    Faulty alerts about unlicensed software.

    In specific areas, the Trojans commonly wrongfully report having actually found some unlicensed applications enabled on the victim’s tool. The sharp after that requires the user to pay the ransom.

    Faulty statements regarding prohibited content.

    In nations where software application piracy is less popular, this technique is not as efficient for the cyber fraudulences. Conversely, the Backdoor.Quasar popup alert may falsely assert to be deriving from a police establishment as well as will certainly report having situated child porn or other illegal data on the device.

    Backdoor.Quasar popup alert may incorrectly declare to be acquiring from a regulation enforcement organization and will certainly report having situated youngster porn or various other illegal data on the tool. The alert will likewise include a requirement for the individual to pay the ransom money.

Technical details

File Info:

crc32: BA656912
md5: d2042ac4c15312dbe80cadb28638a2f1
name: D2042AC4C15312DBE80CADB28638A2F1.mlw
sha1: d81141fca8862dc0704161c95cc1606f785c5034
sha256: 35918d132ee2e809d1b61bda28df3269791b782429a6d79198915f8360ce2e1e
sha512: b1168ef120adbd3b5d2147075f7677df2f770470234ca12f96278c78dd6cdea9bec0a93393088fc7530f6169fcea55892e15d758c90c5a4f5f54a2e51d240922
ssdeep: 12288:41vgTUUDMSzeUei+PLTEy93ucA4a6K3dfrEEVWJbe/3xPX6U:hPT5HhPp
type: PE32 executable (GUI) Intel 80386 Mono/.Net assembly, for MS Windows

Version Info:

Translation: 0x0000 0x04b0
LegalCopyright: Copyright xa9 HP Inc. 2018
Assembly Version:
InternalName: C.PrivateStubWinForm.exe
CompanyName: HP Inc.
ProductName: C.PrivateStubWinForm
FileDescription: C.PrivateStubWinForm
OriginalFilename: C.PrivateStubWinForm.exe

Backdoor.Quasar also known as:

GridinSoft Trojan.Ransom.Gen
Elastic malicious (high confidence)
DrWeb Trojan.PackedNET.148
Cynet Malicious (score: 100)
ALYac Gen:MSIL.Heur2.Lagos.2
Sangfor Trojan.Win32.Save.a
CrowdStrike win/malicious_confidence_100% (W)
Alibaba Backdoor:MSIL/Quasar.f9d75888
Cybereason malicious.4c1531
Cyren W32/MSIL_Kryptik.CCB.gen!Eldorado
Symantec ML.Attribute.HighConfidence
ESET-NOD32 a variant of MSIL/Kryptik.REN
APEX Malicious
Avast Win32:RATX-gen [Trj]
ClamAV Win.Packed.Score-6905873-0
Kaspersky HEUR:Trojan.MSIL.Crypt.gen
BitDefender Gen:MSIL.Heur2.Lagos.2
MicroWorld-eScan Gen:MSIL.Heur2.Lagos.2
Ad-Aware Gen:MSIL.Heur2.Lagos.2
Sophos ML/PE-A + Mal/MsilDyn-G
Comodo TrojWare.MSIL.Agent.GH@60rvah
BitDefenderTheta Gen:NN.ZemsilF.34738.un0@a0bgMCm
TrendMicro TROJ_GEN.R005C0DFB21
Emsisoft Gen:MSIL.Heur2.Lagos.2 (B)
SentinelOne Static AI – Malicious PE
Avira TR/Dropper.MSIL.Gen
eGambit Unsafe.AI_Score_96%
Microsoft Backdoor:MSIL/Quasar.GG!MTB
GData Gen:MSIL.Heur2.Lagos.2
AhnLab-V3 Trojan/Win32.Disfa.C3270649
McAfee GenericRXHY-YA!D2042AC4C153
MAX malware (ai score=87)
Malwarebytes Backdoor.Quasar
Panda Trj/GdSda.A
TrendMicro-HouseCall TROJ_GEN.R005C0DFB21
Ikarus Trojan.MSIL.Crypt
Fortinet MSIL/Kryptik.NZP!tr
AVG Win32:RATX-gen [Trj]

How to remove Backdoor.Quasar virus?

Unwanted application has ofter come with other viruses and spyware. This threats can steal account credentials, or crypt your documents for ransom.
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There is no better way to recognize, remove and prevent PC threats than to use an anti-malware software from GridinSoft2.

Download GridinSoft Anti-Malware.

You can download GridinSoft Anti-Malware by clicking the button below:

Run the setup file.

When setup file has finished downloading, double-click on the setup-antimalware-fix.exe file to install GridinSoft Anti-Malware on your system.

Run Setup.exe

An User Account Control asking you about to allow GridinSoft Anti-Malware to make changes to your device. So, you should click “Yes” to continue with the installation.

GridinSoft Anti-Malware Setup

Press “Install” button.

GridinSoft Anti-Malware Install

Once installed, Anti-Malware will automatically run.

GridinSoft Anti-Malware Splash-Screen

Wait for the Anti-Malware scan to complete.

GridinSoft Anti-Malware will automatically start scanning your system for Backdoor.Quasar files and other malicious programs. This process can take a 20-30 minutes, so I suggest you periodically check on the status of the scan process.

GridinSoft Anti-Malware Scanning

Click on “Clean Now”.

When the scan has finished, you will see the list of infections that GridinSoft Anti-Malware has detected. To remove them click on the “Clean Now” button in right corner.

GridinSoft Anti-Malware Scan Result

Are Your Protected?

GridinSoft Anti-Malware will scan and clean your PC for free in the trial period. The free version offer real-time protection for first 2 days. If you want to be fully protected at all times – I can recommended you to purchase a full version:

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Full version of GridinSoft Anti-Malware

If the guide doesn’t help you to remove Backdoor.Quasar you can always ask me in the comments for getting help.

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  1. GridinSoft Anti-Malware Review from HowToFix site:
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About the author

Robert Bailey

I'm Robert Bailey, a passionate Security Engineer with a deep fascination for all things related to malware, reverse engineering, and white hat ethical hacking.

As a white hat hacker, I firmly believe in the power of ethical hacking to bolster security measures. By identifying vulnerabilities and providing solutions, I contribute to the proactive defense of digital infrastructures.

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