Home Guides Locky ransomware: decrypt files and remove virus (Dec. 2017 upd.)

Locky ransomware: decrypt files and remove virus (Dec. 2017 upd.)

6 min read
The Locky ransomware is a malicious code breed that poses elevated risk due to sizeable stealth, large attack surface and sophisticated money extortion tactic.

Updated in December 2017. The extortion contrivance called the Locky ransomware demonstrates that cybercriminals are obviously in pursuit of new operational mechanisms. Said infection is out-of-the-ordinary because its spreading mode differs from the analogs, and it covers a greater scope of victim data if the attack succeeds. When this infection originally emerged in February 2016, the most prominent indicators of compromise included the .locky extension added at the end of encrypted files, as well as the ransom walkthroughs titled _Locky_recover_instructions.txt. The latest variant circulating since April 2017, though, features quite a few tweaks and enhancements.

Learn how the Locky ransomware has evolved over time

The current Locky spinoff appends the .osiris extension to hostage data entries and drops an updated set of recovery how-to’s named OSIRIS-[4_chars].htm and OSIRIS.bmp. The latter documents show up in all folders the contents of which underwent the detrimental impact of the virus. The affected files, in their turn, assume a weird shape and look similar to this: 8361F0GE–9589–G5F7–C9B07218–D472R0F58112.osiris. The filenames now consist of 36 random hexadecimal characters followed by the version-specific extension.

Locky ransom note and scrambled filenames suffixed with .osiris extension
Locky ransom note and scrambled filenames suffixed with .osiris extension

Of course, the user can no longer open any of these files – not because they were renamed but due to a combo of RSA-2048 and AES-128 ciphers that the ransomware applied. Locky roams through the local drive volumes, external data peripherals such as USB memory sticks or an additional HDD, and network drives. The goal is to find the bits of information with the most widespread extensions. This way, the malware can hit below the belt as it subsequently encodes one’s personal files while disregarding various objects that are auxiliary for the operating system.

Locky ransomware displays decryption steps on desktop background
Locky ransomware displays decryption steps on desktop background

After the encryption job has been finished, the Trojan replaces the admin’s wallpaper with a warning image called DesktopOSIRIS.bmp, which provides step-by-step recommendations regarding data redemption. Replicated in the above-mentioned OSIRIS-[4_chars].htm document, these help files instruct the victim to follow a Tor link for further advice. The linked-to online spot is in fact the Locky Decryptor Page hosted on the dark web, where the hijacked computer user can remit the ransom of 0.5 BTC, or about $800, and download the decoding software afterwards.

Locky ransomware is also non-standard in the context of circulation. Rather than use exploit kits, the miscreants behind it are mass-spamming potential victims with rogue invoices, job offers, scanned images of important documents and the like. The Microsoft Word file that goes with these emails looks innocuous, but it has got a trick in it. When a user opens the file, the text is indiscernible because the document is supposedly “protected”. However, a little prompt says this problem can be rectified by enabling macros. Unfortunately, a lot of users fall for this hype, activate known-vulnerable macros manually and thus allow the attackers to run their code on the computer. If this happens, the cyber offensive is extremely difficult to handle, but not impossible. Read the following tips to find out how you can reinstate your data without paying a cent to the crooks.

Locky ransomware automated removal and data recovery

When faced with ransomware like Locky, 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 Locky 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.

Download and run Combo Cleaner installer on your PC

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.Setup customizations

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.Start initial scan

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.Combo Cleaner scan in progress

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.Scan completed

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.Scan results

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.Stellar Data Recovery main screen

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

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.Recover files

Locky 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 Locky 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.

Remove Locky ransomware using Safe Mode with Networking

Remove Locky ransomware using Safe Mode with Networking

Get rid of Locky ransomware using System Restore

Get rid of Locky ransomware using System Restore

System Restore enables Windows users to roll back all changes made to the OS since the latest restore point creation time. This feature can help eliminate the most persistent ransomware. Before going this route, though, make sure System Restore had been enabled prior to the breach, otherwise the method will be inefficient.

  • 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.Safe Mode with Command Prompt
  • In the Command Prompt window, type cd restore and hit Entercd restore command
  • Type rstrui.exe in the new command line and press EnterType rstrui.exe command
  • 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.System Restore window
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 encrypted 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.

Backups can make your day

Backups can make your day

Not only are you a lucky person in case you’ve been backing up your most important files, but you’re also a wise and prudent user. This isn’t necessarily a resource-heavy activity these days – in fact, some providers of online services are allocating a sufficient size of cloud storage space for free so that every customer can easily upload their critical data without paying a penny. Having removed the Locky ransomware, therefore, all you have to do is download your stuff from the remote server or transfer it all from an external piece of hardware if that’s the case.

Restore previous versions of encrypted files

Restore previous versions of encrypted files

A positive upshot of using this technique depends on whether or not the ransomware has erased the Volume Shadow Copies of the files on your PC. This is a Windows feature that automatically makes and keeps the backups of data elements on the hard drive as long as System Restore is enabled. The cryptoware in question is programmed to switch off the Volume Shadow Copy Service (VSS), but it has reportedly failed to in some cases.

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.

Shadow Explorer

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.

Previous Versions

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

Download Locky removal tool


  1. marc Rousseau

    April 2, 2016 at 3:01 pm

    i’m being asked for 4,1 bitcoin

    have you seen this level of ramsom??


    • admin

      September 3, 2016 at 11:29 am

      That’s a high one, indeed. Is one ore more computers infected? Different cybercriminal groups may set different sizes of the ransom.


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