Another ransomware from STOP family is called Nols. It is just a remake of previous edition and so far, malware researchers confirm that name is the only obvious adjustment on this new threat. As usual, it appends all infected files with .nols extension and this is where security experts derived its identification. The spread tactics to propagate Nols ransomware is unchanged. Makers of this virus are utilizing several misleading scheme to gain entry on random computer system. Hence, the most significant one is through spam email campaign.
One more method that is efficient in deploying Nols ransomware is via file-sharing network. On this scheme, attackers are bundling the malicious code to various downloadable applications like freeware, cracked software, and fake software update. Cyber crooks may also utilize intrusive advertisements to promote the servers that are hosting these dubious files.
When downloaded and executed, Nols ransomware can drop assortment of files on various folders and system directories. One of this substantial file was designed to disable anti-virus program and block its communication to internet, probably to prevent obtaining official update.
To conclude its attack, all target files will get encrypted using a highly complex algorithmic pattern and at the same time, their extension will be appended with .nols. A ransomware note is then generated on each directory with infected files stating that users can only restore them upon paying the ransom money, which is a hefty $980. Though, it is stated in the ransom note that this fee can be reduced to $490 if victims were able to settle the payment within 72 hours.
Similar to other ransomware from this group, malware researchers have yet to find a way to totally decrypt affected files. Though, we can expect alternative solution that can decrypt Nols infected data if it was encrypted via offline keys. Please see more about this tools on the next segment.
How to Remove Nols Ransomware
Ransomware files are placed deeply into the system and on various locations, thus, thorough scanning is vital to totally remove Nols virus. Aside from our suggested tool, you may also run your own security program.
Though affected files may be impossible to decrypt due to complexity of the encryption, you can still try recovery method like alternative tool, Shadow Explorer or Previous Version as described below.
Stage 1: Scan the Computer with Anti-Malware Tool
1. Download free anti-malware scanner called MalwareBytes Anti-Malware.
Malwarebytes Anti-Malware Download Link (this will open a new window)
2. After downloading, install the program. It may run automatically or you have to double-click on the downloaded file MBSetup.exe.
3. Carry out the installation with default setup process.
4. After the installation process, click the Get Started button to launch the program.
5. Continue with the prompts until the main program opens.
6. On the main console, click on Scan to run most complete detection method to find hidden objects associated to Nols ransomware.
7. Scanning may take a while. Please wait until the anti-malware tool is done with the checking.
8. Once the scan has completed, the tool will display the list of detected threats. Remove all identified malicious items and restart the computer if necessary.
Stage 2: Double-check for Nols’s leftover with Microsoft’s Malicious Software Removal Tool
1. Download the free scanner called Malicious Software Removal Tool.
Malicious Software Removal Tool Download Link (this will open a new window)
2. The tool automatically checks the operating system and suggest appropriate download version. Click on Download button to begin. Save the file to a convenient location, preferably on Desktop.
3. After downloading the file, Windows will prompt that download has completed. Click Run to start scanning for Nols ransomware. Another option is to browse the location folder and double click on the file to run.
4. The tool will display Welcome screen, click Next. Please note the message “This tool is not a replacement for an antivirus product.” You must understand that this program is made specifically to find and remove malware, viruses, Trojans, and other harmful elements on the computer. It was not designed to protect the computer.
5. Next, you will see Scan Type. Please choose Full Scan to ensure that all Nols ransom virus entities and other harmful files left on the computer will be found and removed. For advanced computer user, you can opt for Customized Scan, if there are other drives or folders you wanted to include in this scan.
6. Full scan may take a while, please wait for Malicious Software Removal Tool to complete the tasks. However, you may cancel the scan anytime by clicking on the Cancel button.
7. After scanning, the tool will reveal all identified threats. There may be other threats that our first scan fails to detect. Please remove/delete all detected items.
8. When removal procedure is complete, you may now close Malicious Software Removal Tool. We hope that Nols ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.
Stage 3 : Unlocking files with Nols Decryption Tool
Emsisoft Decryptor for STOP Djvu will work only if affected files were encrypted using Offline Keys. Nols ransomware uses the alternate Offline Keys during encryption if there is a problem encountered while communicating to a remote command-and-control server. Follow the guide to start recovering .nols encrypted files.
1. As precautionary measures, we suggest to BACKUP all your .nols encrypted files first on a separate media (USB Drive, Flash Drive, DVD Discs, etc…).
2. Download Emsisoft Decryptor for STOP Djvu from this archive page.
3. Right-click on decrypt_STOPDjvu.exe and click “Run as Administrator“. Windows may prompt “Do you want to allow this app…” just click Yes to continue.
4. By default, the tool will pre-populate the locations where encrypted files were identified. To include other directories, simply click Add Folder button.
5. To start recovering files infected by Nols ransomware, click on Decrypt button to start the procedure. The interface will display status of the current decryption process.
We will update this section once the full decryption tool is on hand. In the meantime, please try other options below if the above procedure is not not effective.
Option 1: Windows Previous Version Tool
Windows Vista and Windows 7 have a feature called Previous Versions. However, this tool is only usable if restore point was made prior to Nols ransomware infection. To use this tool and recover files affected by the virus, please follow these steps:
1. Open My Computer or Windows Explorer.
2. Right-click on the affected files or folders. From the drop-down list, please click on Restore previous versions.
3. New window will open display all backup copy of files and folders you wanted to recover. Choose the appropriate file and click on Open, Copy, or Restore. Restoring selected files overwrites the current encrypted files on the computer.
Option 2: Use ShadowExplorer to restore files encrypted by Nols Ransomware
Just like Previous Version tool, ShadowExplorer is taking advantage of shadow copy created by Windows. This tool allows you to retrieve older version of files before it was encrypted by Nols ransomware.
1. Download ShadowExplorer from the official web site.
2. Install the program with the default settings.
3. The program should run automatically after installation. If not, double-click on ShadowExplorer icon.
4. You can see the drop-down list on top of the console. Please select proper drive and the most recent point-in-time shadow copies of files you wish to restore prior to Nols ransomware infection.
5. Right-click on the Drive, Folder, or File you wish to restore and click Export…
6. Lastly, ShadowExplorer will prompt for location where you want to save the copy of recovered files.