The evolution of the NM4 ransomware family has spawned a spinoff that encrypts a victim’s personal files and blemishes them with the new .NMCRYPT extension.
Some of the big players on the ransomware battleground chose to follow the money and join the cryptocurrency mining rush instead. Others stick around and continue to release updates to their blackmail contrivances – in some cases, this looks like a reanimation of strains everyone considered obsolete. The NMoreira ransomware lineage, also referred to as NM4, has been in the wild since November 2016, so it’s one of the oldies. This perpetrating program has not undergone updates for almost a year, and it’s not until April 2018 that its .NMCRYPT file variant has popped up. This iteration hasn’t introduced any tangible qualitative changes other than the new extension being affixed to hostage data.
The common infection methodology is still diversified and includes the malspam, booby-trapped software updates, and hacked RDP vectors. The spam route, though, prevails and is being reported most frequently. People receive emails that instantly draw their attention, such as invoices, receipts, missed delivery notifications, CVs or similar. The files attached to these phishing messages either contain the ransomware binary or trigger the attack chain by downloading the payload in a furtive fashion. Once the culprit’s process has been executed inside the host, it scans all hard disk partitions and network shares for personal documents, videos, pictures, databases and other potentially valuable information. To this end, it compares all data items it comes across against a predefined array of file formats corresponding to the most common file types.
Once the ransomware has located the entirety of personal files on the infected machine, it gets down to the encryption routine. To make data inaccessible, the Nmcrypt virus utilizes a fusion of AES-256 and RSA-2048 ciphers. Consequently, the decryption is feasible with the RSA private key that’s kept by the operators of this ransomware campaign. The modifications aren’t restricted to scrambling the deep structure of these files, though. The toxic program also tweaks filenames by appending the .NMCRYPT string to each one. The transition of an image named 3.jpg to 3.jpg.NMCRYPT demonstrates this external alteration. Additionally, the pest drops a file containing recovery guidance into all directories with encrypted data and onto the desktop. It is named ‘Recovers your files.html’. Interestingly, this ransom note is identical to the one dropped by the previous versions of NMoreira, so the crooks didn’t bother editing what works anyway.
The HTML ransom manual instructs the plagued user to visit a decryption service page using Tor browser. The page asks for a ‘donation’ amounting to $6,705 worth of Bitcoin, after which the attackers promise to send the private key required for data recovery. There are several caveats to following the felons’ recommendations. First, the sum is really hefty. Secondly, no one can possibly guarantee that the threat actors will actually provide the key even after the payment. It is much more reasonable to start with some of the old school practices of data recovery.
Nmcrypt ransomware automated removal and data recovery
Owing to an up-to-date database of malware signatures and intelligent behavioral detection, the recommended software can quickly locate the infection, eradicate it and remediate all harmful changes. So go ahead and do the following:
1. Download and install the antimalware tool. Open the solution and have it check your PC for PUPs and other types of malicious software by clicking the Start Computer Scan button
2. Rest assured the scan report will list all items that may harm your operating system. Select the detected entries and click Fix Threats to get the troubleshooting completed.
Data recovery toolkit to the rescue
Some strains of ransomware are known to delete the original files after the encryption routine has been completed. As hostile as this activity appears, it can play into your hands. There are applications designed to revive the information that was obliterated because of malfunctioning hardware or due to accidental removal. The tool called Data Recovery Pro by ParetoLogic features this type of capability therefore it can be applied in ransom attack scenarios to at least get the most important files back. So download and install the program, run a scan and let it do its job.
Nmcrypt ransomware manual removal and file recovery
Some ransomware strains terminate themselves after completing the encryption job on a computer, but some don’t. Furthermore, the Nmcrypt blackmail virus may prevent victims from using popular antimalware tools in order to stay on board for as long as possible. Under the circumstances, it may be necessary to utilize the Safe Mode with Networking or System Restore functionality.
- Restart the machine. When the system begins loading back up, keep pressing the F8 key with short intervals. The Windows Advanced Options Menu (Advanced Boot Options) screen will appear.
- Use arrow keys to select Safe Mode with Networking and hit Enter. Log on with the user account infected by the ransomware.
- Click on the Search icon next to the Start menu button. Type msconfig in the search field and select the System Configuration option in the results. Go to the Boot tab in the upper part of the GUI.
- Under Boot options, select Safe boot and click the Apply button. A prompt will appear to reboot the computer so that the changes take effect. Select the Restart option and wait for the system to load into Safe Mode. Again, log on with the ransomware-stricken user account.
In Safe Mode, the ransom Trojan won’t keep security software from running or otherwise thwart troubleshooting. Open your preferred web browser, download and install an antimalware tool of choice and start a full system scan. Have all the detected ransomware components removed in a hassle-free way.
- Open Windows Advanced Options Menu as described in the previous section: hit F8 repeatedly when the PC is starting up. Use arrow keys to highlight the Safe Mode with Command Prompt entry. Hit Enter.
- In the Command Prompt window, type cd restore and hit Enter
- Type rstrui.exe in the new command line and press Enter
- When the System Restore screen pops up, click Next, select a restore point that predates the contamination, and use the application’s controls to roll back the system to this earlier state.
Be advised that even after the ransomware is removed, files will still be encrypted and inaccessible. The malicious code cleanup part, however, is important because it keeps a relapse of the infection from occurring further on and eliminates all opportunistic malware.
Ways of non-ransom recovery of .NMCRYPT files
Cracking the crypto used by this ransom Trojan is more of a science fiction thing rather than an attainable prospect for the masses. This is why the troubleshooting in predicaments of this sort is a matter of two approaches: one is to pay the ransom, which isn’t an option for many victims; and the other is to apply instruments that take advantage of the ransomware’s possible weaknesses. If the latter is your pick, the advice below is a must-try.
Checking one’s options regarding this workaround is doable in two ways: through the Properties menu of each file or by means of the remarkable open-source tool called Shadow Explorer. We recommend the software-based way because it’s automated, hence faster and easier. Just install the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
Alternatively, you can leverage the Previous Versions feature, which is native to Windows operating system. This method is more cumbersome that the use of ShadowExplorer, but it can help restore the most important individual files on condition that the ransomware failed to disable the Volume Snapshot Service on the computer. Right-click on a file of choice and select Properties. Then, go to the Previous Versions tab as illustrated below.
Go ahead and pick the file’s latest backup version on the list. Use the Copy or Restore buttons to reinstate this object to a new path or to its original folder, respectively.
Ransomware Prevention Tips
To avoid the Nmcrypt ransomware and other file-encrypting infections in the future, follow several simple recommendations:
- Toggle your email provider’s anti-spam settings to filter out all the potentially harmful incoming messages. Raising the bar beyond the default protection is an important countermeasure for ransom Trojans.
- Define specific file extension restrictions in your email system. Make sure that attachments with the following extensions are blacklisted: .js, .vbs, .docm, .hta, .exe, .cmd, .scr, and .bat. Also, treat ZIP archives in received messages with extreme caution.
- Rename the vssadmin.exe process so that ransomware is unable to obliterate all Shadow Volume Copies of your files in one shot.
- Keep your Firewall active at all times. It can prevent crypto ransomware from communicating with its C&C server. This way, the threat won’t be able to obtain cryptographic keys and lock your files.
- Back up your files regularly, at least the most important ones. This recommendation is self-explanatory. A ransomware attack isn’t an issue as long as you keep unaffected copies of your data in a safe place.
- Use an effective antimalware suite. There are security tools that identify ransomware-specific behavior and block the infection before it can do any harm.
These techniques are certainly not a cure-all, but they will add an extra layer of ransomware protection to your security setup.
Revise your security status
Post-factum assessment of the accuracy component in malware removal scenarios is a great habit that prevents the comeback of harmful code or replication of its unattended fractions. Make sure you are good to go by running an additional safety checkup.