.lock file virus: recovery and ransomware removal

The .lock extension added to filenames indicates a ransomware attack where the culprit is the Nulltica virus, which utilizes a very unusual spreading vector.

The online extortion landscape is currently dominated by rather dull ransomware samples that don’t differ much from one another, except perhaps some heavyweights like Locky and Cerber that sail their own boat. When a new strain is released that stands out from the rest in some way, it becomes almost a buzzword. This sort of applies to the Nulltica ransomware originally discovered on September 4, 2017. It leverages AES-256 cryptosystem to deny access to files and then appends them with the .lock extension. The offbeat thing about this specimen is that it exhibits hallmarks of spyware. In particular, it steals a victim’s Facebook access credentials and sends trojanized messages to their contacts. The file embedded in these rogue messages invokes a surreptitious script that installs the Nulltica virus onto recipients’ machines. Therefore, this ransomware employs a really intricate self-distribution technique.

The code of Nulltica is based off of Hidden Tear, a proof-of-concept ransomware infection outsourced via GitHub in 2015. As opposed to dozens of other Hidden Tear derivatives, though, this one is more professionally fine-tuned to deploy cyber blackmail attacks. It goes equipped with a graphical user interface titled ‘Information’, which pops up after the contamination and data encryption has been completed. Prior to this, Nulltica scans local hard disk volumes and removable drives for a predefined set of file types. Once a matching data entry is spotted, the infection encrypts it and concatenates the above-mentioned .lock suffix. For instance, a sample image named ‘Orchard.bmp’ will assume the form of ‘Orchard.bmp.lock’.

The GUI of the .lock file virus instructs the victim to pay $50 worth of Bitcoin to the threat actors’ BTC address. According to the rescue note, all it takes to decrypt data after the payment is click the built-in button that says, “Unlock and remove the program.” However, the only thing that actually happens is that the files will get an extra .unlock extension (‘Orchard.bmp.lock.unlock’ in the above example) but will still remain encrypted and inaccessible. So, unfortunately, Nulltica is either buggy in its current state or deliberately doesn’t go with a working data restoration functionality under the hood. Under the circumstances, the only options left circle around forensic methods of .lock files recovery described in detail below.

.lock file (Nulltica) ransomware automated removal and data recovery

When faced with ransomware like .lock file (Nulltica), one of the best shortcuts in terms of removal is to use Combo Cleaner, a lightweight and incredibly effective application with PC security and optimization features under the hood. It detects and thoroughly deletes threats while giving you insights into the overall health of your computer.

This program’s protection power spans modules that forestall all known types of malware, including ransomware and browser hijackers, and take your online security to the next level by blocking phishing sites and other suspicious web pages. Follow these simple steps to eliminate the infection for good:

1. Download Combo Cleaner installer.

Download .lock file (Nulltica) remover

^{Combo Cleaner scans your PC with no strings attached, but you’ll have to buy its fully functional version to remove the threats it detects. The disk optimization tools that find large files and duplicates are free to use.}

2. Open the CCSetup.exe file to get started. Several subsequent screens will allow you to make initial customizations so that the program works exactly as you need from the get-go.

3. The installation will be followed by an update of malware signatures. Once this process is through, click the Start Scan button in the left-hand sidebar.

4. Combo Cleaner will then check system locations that are most often polluted by Windows malware. The first scan can take a while to finish.

5. Combo Cleaner will display a system tray notification as soon as the scan is over. Click the Resolve found threats button to view the results.

6. The scan summary shows the names and types of the detected threats as well as their statuses and locations. Click the Remove all threats button and follow further on-screen prompts to get rid of these items.

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 Stellar Data Recovery features this type of a capability and therefore it can be applied in ransom attack scenarios to at least get the most important files back. So use the app to get an idea of what data can be restored and let it do the recovery job. Here is a step-by-step walkthrough:

1. Download and install Stellar Data Recovery.

Download Stellar Data Recovery

2. Open the application, select the types of recoverable files to look for, and click Next.

3. Choose the areas you want the tool to recover from and click the Scan button.

4. Having scanned the specified locations, the program will display a notification about the total amount of recoverable data. Close the dialog and click the Recover button. This will hopefully help you get some of your valuable files back.

.lock file (Nulltica) 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 .lock file (Nulltica) 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.

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 .lock extension 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.

Ransomware Prevention Tips

To avoid .lock file (Nulltica) ransomware and other file-encrypting infections in the future, follow several simple recommendations:

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. Another benefit of using the antimalware tool is that it will keep ransomware threats from intruding on your computer further on.

Download .lock file (Nulltica) removal tool