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Remove Nemucod Ransomware and Restore .Crypted Encrypted Files

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decrypt-text.sensorstechforumA new javascript type of ransomware has been reported to infect users globally. This crypto malware is particularly devastating because it uses an immensely strong cypher to encrypt the files of affected users, making them impossible to decrypt directly even if a very powerful system is used. Nemucod also demands a ransom payment in BTC from affected users which equals to approximately 200 USD. The good news is that Emsisoft researchers have discovered a decryptor and we strongly advise following the step-by-step removal instructions below to remove Nemucod Ransomware and unlock your files.

NameNemucod
TypeRansomware
Short DescriptionEncrypts user files and asks around 0.5 BTC for decryption.
SymptomsThe user may witness a file “DECRYPT.txt” on his desktop and the ransom message to open in a text document every time Windows starts.
Distribution MethodVia malicious urls or email attachments.
Detection ToolDownload Malware Removal Tool, to See If Your System Has Been Affected by Nemucod
User Experience Join our forum to discuss Nemucod.
Data Recovery ToolWindows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

Nemucod Ransomware – Distribution

To infect computers, Nemucod may use spam e-mails to redirect users to either website that automatically download and execute a malicious payload carrying file or an infected e-mail attachment. Here is an example of such spam e-mail:

spam-email-sensorstechforum

The infected attachments are usually Micorosoft Office documents or Adobe Reader .PDF files with infected macros. As soon as the macro has been enabled, Nemucod may execute a malicious script that drops its payload.

Nemucod Ransomware In Detail

Symantec researchers report that once activated on the computer; the malicious JavaScript may drop the following modules of Nemucod in several key Windows locations:

In %Temp%
a0.exe
a1.exe
a2.exe
a.txt
On %Desktop% of the User’s Profile
DECRYPT.txt

Nemucod ransomware may also create registry entries to set the malicious executables to run everytime Windows boots up. The keys that are reported are the following:

In HKEY_CLASSES_ROOT
Crypted\shell\open\command\”(Default)”=notepad.exe “%Temp%\a.txt”
.crypted\”(Default)”=Crypted
In HKEY_CURRENT_USER
SOFTWARE\Microsoft\Windows\CurrentVersion\Run\”Crypted”=%Temp%\a.txt

These keys are specifically created to run the ransom note (“a.txt”) every time Windows starts.

Nemucod encrypts the most widely used file types. To do this, it uses an escalated command In Windows command prompt. The command for encryption is reported by researchers to be the following:

→ For (var I = 67; I <= 90; i++) { Fp.WriteLine(“dor /B “ + cq + String.fromcharCode(i) + “:” + cs + cq + “ && for /r” + cq + String.fromCharCode(i) + “:” + cs + cq + “ %%i in ( file extensions which Nemucod encrypts ) do (REN “ + cq + “%%i” + cq + “%%i” + cq + “ “ + cq + “%%~nxi.crypted” + cq + “&call “ + fn + “.exe” + cq + “%%i.crypted” + cq + “)”); };

The command creates a call to action for the encryption module of the ransomware. After it, the malware starts looking for files of the following types:

→ .zip .rar .7z .tar .gz .xls .xlsx .doc .docx .pdf .rtf .ppt .pptx .sxi .odm .odt .mpp .ssh .pub .gpg .pgp .kdb .kdbx .als .aup .cpr .npr .cpp .bas .asm .cs .php .pas .vb .vcproj .vbproj .mdb .accdb .mdf .odb .wdb .csv .tsv .psd .eps .cdr .cpt .indd .dwg .max .skp .scad .cad .3ds .blend .lwo .lws .mb .slddrw .sldasm .sldprt .u3d .jpg .tiff .tif .raw .avi .mpg .mp4 .m4v .mpeg .mpe .wmf .wmv .veg .vdi .vmdk .vhd .dsk Source:Symantec

The files encrypted are not fully encoded, instead only a part of them is cyphered (usually 32 or 64 bits of the file), which is more than enough to make them corrupt. Then, the ransomware appends, the .crypted file extension to them. The encrypted files look like the following:

  • New Text Document.txt.crypted

Furthermore, regarding file encryption, the Trojan is believed to use modules from 7zip which it may download via connecting to its command and control domains. The C&C servers of the cyber-criminals are reported to be the following:

  • Ujjwaljeweller(.)com
  • Topikriau(.)com
  • yc4tuna(.)com
  • yingyigoo(.)com
  • xn--oi2bq3ygphw3bbzh(.)com

After encrypting the data, Nemucod executes its ransom note for the affected user to see. The notification is reported to be the following:

→ “ATTENTION!
All your documents, photos, databases and other important personal files were encrypted using strong RSA-1024 algorithm with a unique key.
To restore your files you have to pay 0.52985 BTC(bitcoins).
Please follow this manual:
1.Create Bitcoin wallet here:
https://blockchain.info/wallet/new
2.Buy 0.52985 BTC wth cash, using search here:
https://localbitcoins.com/buy_bitcoins
3.Send 0.52985 BTC to this Bitcoin address:
{cyber-criminals bitcoin address}
4.Open one of the following links in your browser to download decryptor:
{several web links for download that are linked to the cyber-criminals’ domains}
5.Run decryptor to restore your files.
PLEASE REMEMBER:
-If you do not pay in 3 days YOU LOOSE ALL YOUR FILES.
-Nobody can help you except us.
-It’s useless to reinstall Windows, update antivirus software, etc.
-Your files can be decrypted only after you make payment.
-You can find this manual on your desktop (DECRYPT.txt).”

Remove Nemucod Ransomware and Decrypt .Crypted Files

The removal of the ransomware is rather simple than complicated. Since it may have an active connection to several remote servers, we advise following the removal instructions below to break this connection and remove the malicious files and entries. This can happen by downloading an advanced anti-malware tool and scanning the computer in offline Safe Mode with no third-party applications running and no active connection.

If you want to decrypt your files, you are lucky, because this is one of the few ransomware variants that have a working decryptor. The credit for that goes to Emsisoft researchers who have developed Nemucod decrypter. To see how to work with the decryptor and revert your files, please check the instructions in step number 4 below.

1. Boot Your PC In Safe Mode to isolate and remove Nemucod

Boot Your PC Into Safe Mode

1. For Windows 7,XP and Vista. 2. For Windows 8, 8.1 and 10.

For Windows XP, Vista, 7 systems:

1. Remove all CDs and DVDs, and then Restart your PC from the “Start” menu.
2. Select one of the two options provided below:

For PCs with a single operating system: Press “F8” repeatedly after the first boot screen shows up during the restart of your computer. In case the Windows logo appears on the screen, you have to repeat the same task again.

donload_now_140

For PCs with multiple operating systems: Тhe arrow keys will help you select the operating system you prefer to start in Safe Mode. Press “F8” just as described for a single operating system.

donload_now_140

3. As the “Advanced Boot Options” screen appears, select the Safe Mode option you want using the arrow keys. As you make your selection, press “Enter“.

4. Log on to your computer using your administrator account

donload_now_140

While your computer is in Safe Mode, the words “Safe Mode” will appear in all four corners of your screen.

Step 1: Open the Start Menu

donload_now_140

Step 2: Whilst holding down Shift button, click on Power and then click on Restart.
Step 3: After reboot, the aftermentioned menu will appear. From there you should choose Troubleshoot.

donload_now_140

Step 4: You will see the Troubleshoot menu. From this menu you can choose Advanced Options.

donload_now_140

Step 5: After the Advanced Options menu appears, click on Startup Settings.

donload_now_140

Step 6: Click on Restart.
donload_now_140

Step 7: A menu will appear upon reboot. You should choose Safe Mode by pressing its corresponding number and the machine will restart.

2. Remove Nemucod with SpyHunter Anti-Malware Tool

Remove Nemucod with SpyHunter Anti-Malware Tool

1. Install SpyHunter to scan for and remove Nemucod.2. Scan with SpyHunter to Detect and Remove Nemucod.
Step 1:Click on the “Download” button to proceed to SpyHunter’s download page.

donload_now_140
It is highly recommended to run a scan before purchasing the full version of the software to make sure that the current version of the malware can be detected by SpyHunter.

Step 2: Guide yourself by the download instructions provided for each browser.
Step 3: After you have installed SpyHunter, wait for it to automatically update.

pets-by-myway-ads-virus

Step1: After the update process has finished, click on the ‘Scan Computer Now’ button.
pets-by-myway-ads-virus
Step2: After SpyHunter has finished scanning your PC for any Nemucod files, click on the ‘Fix Threats’ button to remove them automatically and permanently.
pets-by-myway-ads-virus
Step3: Once the intrusions on your PC have been removed, it is highly recommended to restart it.

3. Back up your data to secure it against infections and file encryption by Nemucod in the future

Back up your data to secure it against attacks in the future

IMPORTANT! Before reading the Windows backup instructions, we highly recommend to back up your data automatically with cloud backup and insure it against any type of data loss on your device, even the most severe. We recommend reading more about and downloading SOS Online Backup .

To back up your files via Windows and prevent any future intrusions, follow these instructions:

1. For Windows 7 and earlier 1. For Windows 8, 8.1 and 10 1. Enabling the Windows Defense Feature (Previous Versions)

1-Click on Windows Start Menu
backup-1
2-Type Backup And Restore
3-Open it and click on Set Up Backup
w7-backup3
4-A window will appear asking you where to set up backup. You should have a flash drive or an external hard drive. Mark it by clicking on it with your mouse then click on Next.
backup-3
5-On the next window, the system will ask you what do you want to backup. Choose the ‘Let Me Choose’ option and then click on Next.
backup-4
6-Click on ‘Save settings and run backup’ on the next window in order to protect your files from possible attacks by Nemucod.
backup-5

1-Press Windows button + R
filehistory-1
2-In the window type ‘filehistory’ and press Enter
filehistory-2
3-A File History window will appear. Click on ‘Configure file history settings’
filehistory-3
4-The configuration menu for File History will appear. Click on ‘Turn On’. After its on, click on Select Drive in order to select the backup drive. It is recommended to choose an external HDD, SSD or a USB stick whose memory capacity is corresponding to the size of the files you want to backup.
filehistory-4
5-Select the drive then click on ‘Ok’ in order to set up file backup and protect yourself from Nemucod.

1- Press Windows button + R keys.
sysdm
2- A run windows should appear. In it type ‘sysdm.cpl’ and then click on Run.
windows-defense2
3- A System Properties windows should appear. In it choose System Protection.
windows-defense3
5- Click on Turn on system protection and select the size on the hard disk you want to utilize for system protection.
6- Click on Ok and you should see an indication in Protection settings that the protection from Nemucod is on.
windows-defense1
Restoring a file via Windows Defense feature:
1-Right-click on the encrypted file, then choose Properties.
file-restore1
2-Click on the Previous Versions tab and then mark the last version of the file.
file-restore2
3-Click on Apply and Ok and the file encrypted by Nemucod should be restored.

4. Restore files encrypted by Nemucod

Restore Files Encrypted by Nemucod

Fortunately, Emsisoft have come up with a decrypter for this ransomware. You can download it by visiting the Emsisoft Download web page below:

Download Nemucod Decrypter

After downloading it, use the following instructions:
1.Drag 1 encrypted and 1 original file to the downloaded file decrypt_nemucod.exe. It will reveal your unique decryption key.
2.Click on Ok when the key is found.
3.Click on Add File(s) to add the drive or files which you want to decrypt.
4.Wait for file decryption.

Optional: Using Alternative Anti-Malware Tools

Remove Nemucod Using Other Alternative Tools

STOPZilla Anti Malware
1. Download and Install STOPZilla Anti-malware to Scan for And Remove Nemucod.
Step 1: Download STOPZilla by clicking here.
Step 2: A pop-up window will appear. Click on the ‘Save File’ button. If it does not, click on the Download button and save it afterwards.
pets-by-myway-ads-virus
Step 3: After you have downloaded the setup, simply open it.
Step 4: The installer should appear. Click on the ‘Next’ button.
pets-by-myway-ads-virus
Step 5: Check the ‘I accept the agreement’ check circle if not checked if you accept it and click the ‘Next’ button once again.
pets-by-myway-ads-virus
Step 6: Review and click on the ‘Install’ button.
pets-by-myway-ads-virus
Step 7: After the installation process has completed click on the ‘Finish’ button.

2. Scan your PC with STOPZilla Anti Malware to remove all Nemucod associated files completely.
Step 1: Launch STOPZilla if you haven’t launched it after install.
Step 2: Wait for the software to automatically scan and then click on the ‘Repair Now’ button. If it does not scan automatically, click on the ‘Scan Now’ button.
pets-by-myway-ads-virus
Step 3: After the removal of all threats and associated objects, you should Restart your PC.

NOTE! Substantial notification about the Nemucod threat: Manual removal of Nemucod requires interference with system files and registries. Thus, it can cause damage to your PC. Even if your computer skills are not at a professional level, don’t worry. You can do the removal yourself just in 5 minutes, using a malware removal tool.
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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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