Ransom:Win32/StopCrypt.AK!MTB is a computer virus that blocks users from accessing their data. This threat is notorious for encrypting the target files with sophisticated methods to make it unusable. The objective is to entice victims to pay the ransom demand to hackers. If you remain unpaid within the given period, Ransom:Win32/StopCrypt.AK!MTB threatens to delete the unique private key that will make the encrypted files permanently useless.

How does it infect the computer?

Ransom:Win32/StopCrypt.AK!MTB viruses normally reach their target users via spam email messages, infected software installers, botnets, drive-by downloads, malicious ads, and fake software updates. Hence, it is through a mass-mailing campaign that Ransom:Win32/StopCrypt.AK!MTB was able to spread quickly and more efficiently. Technically, this is called phishing email because the attackers are masquerading as legitimate companies or brands, and the email was designed to appear as common business messages usually related to deliveries, invoices, payments, taxes, product inquiries, and other business-related matters.

The attached files are Ransom:Win32/StopCrypt.AK!MTB is embedded is often in the form of Doc, Xls, Pdf, Zip, or Html. This social engineering tactic was found to be highly effective in distributing malware due to the clever use of online communication and contact references.

Once Ransom:Win32/StopCrypt.AK!MTB is inside the computer; it drops copies of itself in System folder and in different directories depending on which variant is infecting the computer. As of today, there are more than 250 variants of this ransomware, and here is a list of just a few.

Lyli, Copa, Kolz, Npph, Geno, Ogdo, Kasp, Boop, Vari, Oonn, Nile, Kook, Erif, Kuus, Maas, Zida, Pykw, Moba, Vawe, Usam, Tabe, Nypd, Zwer, Kkll, Nlah, Zipe, Pezi, Covm, Koti, Mzlq, Sqpc, Mpal, Qewe, Lezp, Lalo, Mpaj

How does this malware operate?

The main objective of Ransom:Win32/StopCrypt.AK!MTB is to extort money from computer users, and to accomplish this goal, it will execute the following tasks:.

  • Infects the computer by exploiting different vulnerabilities, especially RDP.
  • It encrypts the target files with a complex algorithm using RSA Salsa20 technology.
  • Appends the virus filename to all encrypted files.
  • Generate the ransom note containing the instructions in obtaining the decryption tool.
  • Virus remains active on the computer to encrypt newer files.
Technical Details
Virus Name: Ransom:Win32/StopCrypt.AK!MTB
Threat Type: STOP/DJVU Ransomware, Crypto-Virus
Similar Detections: Alibaba : Ransom:Win32/StopCrypt.6e81788d
Avast : Win32:DropperX-gen
Avira : TR/AD.VidarStealer.fjimx
BitDefender : Trojan.GenericKD.43929738
ClamAV : Win.Trojan.Tofsee-9770082-1
DrWeb : Trojan.Siggen10.32818
F-Secure : Trojan.TR/AD.VidarStealer.fjimx
Fortinet : W32/Kryptik.HGNJ!tr
Ikarus : Trojan.Win32.Crypt
Kaspersky : HEUR:Trojan.Win32.Chapak.gen
Malwarebytes : Trojan.MalPack.GS
McAfee : Trojan-FSUC!6463FA6A18BF
NANO-Antivirus : Trojan.Win32.Chapak.hxpnhf
Panda : Trj/GdSda.A
Rising : Ransom.StopCrypt!8.11C05 (TFE:5:xfgOqVjWH2N)
Sophos AV : Mal/Generic-S
Symantec : ML.Attribute.HighConfidence
TrendMicro : Trojan.Win32.WACATAC.THICOBO
Webroot : W32.InfoStealer.Zeus

How to remove Ransom:Win32/StopCrypt.AK!MTB?

To totally remove Ransom:Win32/StopCrypt.AK!MTB from the computer and get rid of relevant viruses and trojans, please execute the procedures as stated on this page. Make sure that you have completely scanned the system with the suggested malware removal tools and virus scanners.

Quick Fix - Scan the PC with Combo Cleaner for Windows

Combo Cleaner is a trusted PC security and optimization tool equipped with a powerful virus and malware detection engine. This program can get rid of hazardous viruses like Ransom:Win32/StopCrypt.AK!MTB through this procedure.

1. Download the application from the following page:

2. Save the file to your preferred location.

3. Double-click the downloaded file CCSetup.exe and install with the default settings.

CC for Windows Installation

4. At the end of the setup process, click Finish to run Combo Cleaner.

5. The tool will update the signature file, please wait for this process to complete.

6. To begin checking for threats like Ransom:Win32/StopCrypt.AK!MTB, click on the Start Scan button. Wait for this scan to finish.

CC for Windows Start Scan

7. At the end of the scan process, click on Remove all threats to delete the Ransom:Win32/StopCrypt.AK!MTB virus, including all malicious objects from the computer.

Free features of Combo Cleaner for Windows include Disk Cleaner, Big Files finder, Duplicate files finder, and Uninstaller. To use antivirus, privacy scanner, and to delete identified threats, users have to upgrade to a premium version.

Please continue with the succeeding removal procedures if you are comfortable manually getting rid of the virus and malicious items linked to it.

Step 1 : Start Windows in Safe Mode With Networking

The method of running Windows in Safe Mode before running a virus scan is effective in getting rid of Ransom:Win32/StopCrypt.AK!MTB. This process can prevent most viruses and malware from loading, making it easier to detect and remove them.

1. On the Windows Search bar, please type msconfig.

Screenshot of MSConfig Command

2. Select and open System Configutation on the list of found results.

3. Once you are in the System Configuration window, go to the Boot tab.

Screenshot of SafeBoot

4. Under the Boot Options area, please check Safe Boot and select Network. This will allow Windows to boot in Safe Mode with Networking.

5. Lastly, click on Apply and OK to save the changes.

6. Please restart Windows.

Do not forget to restore the normal boot process of Windows after running the virus scan. Simply repeat the method above, and this time, uncheck the Safe Boot option to run Windows normally.

Step 2 : Run a virus scanner

To remove Ransom:Win32/StopCrypt.AK!MTB, we suggest that you scan the infected computer with this powerful virus removal tool. It can detect and get rid of Trojans, viruses, malware, and adware from the infected computer. To fully protect the computer against Ransom:Win32/StopCrypt.AK!MTB or similar attacks, you can activate Sophos to have real-time scanning and complete defense against all forms of threats.

1. Download Sophos Virus Removal Tool from the link below. Save the file on your computer where you can easily access it.

2. Once the download completes, browse the location of the file. Double-click to run the program and begin the install process.

3. On the first window of installation wizard, click Next to continue. Then, it will display the program’s License Agreement. You need to Accept the terms in order to proceed. If Windows prompts for User Account Control, please click Yes to proceed.

Screenshot of Sophos EULA Page

4. On succeeding windows, click Next or Continue to carry on with the installation. After completing the installation process, Launch Sophos Virus Removal Tool.

5. An internet connection is required when running this scanner in order to download important updates. Make sure that everything is up-to-date to effectively remove viruses like Ransom:Win32/StopCrypt.AK!MTB.

6. Click the Start Scanning button to  carry out the Scan. This will check the system for the presence of malicious objects, malware, and viruses. The tool reveals items that were found linked to Ransom:Win32/StopCrypt.AK!MTB and other suspicious entities. Be sure to remove all identified threats.

Screenshot of Sophos Virus Scan

After executing the above instructions, Ransom:Win32/StopCrypt.AK!MTB should have been completely removed from the computer. If there are still signs of infection or the computer is displaying unusual behaviors, please continue with the remaining procedures.

Another alternative for Windows 10/11 users is to scan the computer with Microsoft Defender Offline. This will run a virus scan in the recovery environment.

Step 3 : Double Check with Windows Security Apps

Microsoft Windows has a built-in security application that you can use to double-check if your computer is still infected with Ransom:Win32/StopCrypt.AK!MTB. For Windows 10/11 users, please run Windows Security.

Windows 10 / 11 Instructions:

Windows Security is a free tool that was built to help you remove Ransom:Win32/StopCrypt.AK!MTB, viruses, and other malicious items from Windows 10/11 systems. Follow these procedures to scan your computer with the tool:

1. Tap or click the Search charm, search for Windows Security, and then open the application.

Image of Windows Security Search

2. On the Home tab, click Virus and threat protection from the sidebar.

3. On the main window, click on Scan Options. Then, click on Full Scan button.

Image of Scan Options

4. Lastly, click on the Scan now button to start scanning for the presence of Ransom:Win32/StopCrypt.AK!MTB. The process may take a while to complete.

5. After the scan, Delete/Quarantine identified threats, whether they were relevant to Ransom:Win32/StopCrypt.AK!MTB or not. You may now restart Windows to complete the virus removal process.

For older versions of Windows, you can scan the computer for free with the Microsoft Malicious Software Removal Tool (MSRT 64-Bit). It is a stand-alone virus scanner tool that targets prevalent malware groups.

How to protect the computer from Ransom:Win32/StopCrypt.AK!MTB?

The initial defense that comes to mind for any computer user is to install an anti-virus or anti-malware program. This move is sensible and probably the most practical way to protect the computer against a Ransom:Win32/StopCrypt.AK!MTB attack. Hence, keep in mind that having security software does not guarantee full protection. The majority of the prevention still lies in being cautious of users, and therefore, we are providing the following information as guidelines to protect the computer from virus infection.

Avoid Malicious Websites

There are enormous numbers of websites that were made for the primary purpose of spreading Ransom:Win32/StopCrypt.AK!MTB. Normally, these sites are involved in integrating malicious pop-up and browser hijacker, that will eventually cause further virus infections. Avoid such websites.

Ignore and Delete Phishing Emails

The mass-mailing of computer viruses gives the attackers the luxury of spreading their malicious code in just one send-off. This will arrive in the inbox as an email that appears to be from a legitimate organization. So, if you receive an unexpected email with a link or an attached file, better delete it immediately.

Do Not Click a Suspicious Link

Links from social media, forums, and blog sites are sometimes being utilized by attackers to drive web users to a malicious page that contains malicious code. Therefore, do not just click on any link, especially if it looks suspicious. Accidental access to the destination site may lead to a Ransom:Win32/StopCrypt.AK!MTB infection.

Be Careful When Downloading Files

Cracked software, serial key generators, and several freeware are seen as another method that spreads the Ransom:Win32/StopCrypt.AK!MTB virus. Avoid acquiring these types of applications, and if there is a need to download freeware or shareware, be sure to obtain it from the official website or trusted providers.

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